diff --git a/.rubocop_todo.yml b/.rubocop_todo.yml
index 864d85f1..d899959e 100644
--- a/.rubocop_todo.yml
+++ b/.rubocop_todo.yml
@@ -83,83 +83,6 @@ Metrics/ModuleLength:
 Metrics/PerceivedComplexity:
   Max: 21
 
-# Offense count: 4
-Naming/ConstantName:
-  Exclude:
-    - 'lib/faraday/options/env.rb'
-    - 'lib/faraday/response/raise_error.rb'
-
-# Offense count: 2
-# Configuration parameters: NamePrefix, NamePrefixBlacklist, NameWhitelist, MethodDefinitionMacros.
-# NamePrefix: is_, has_, have_
-# NamePrefixBlacklist: is_, has_, have_
-# NameWhitelist: is_a?
-# MethodDefinitionMacros: define_method, define_singleton_method
-Naming/PredicateName:
-  Exclude:
-    - 'spec/**/*'
-    - 'lib/faraday/rack_builder.rb'
-    - 'lib/faraday/request/multipart.rb'
-
-# Offense count: 13
-# Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
-# AllowedNames: io, id, to, by, on, in, at, ip, db
-Naming/UncommunicativeMethodParamName:
-  Exclude:
-    - 'lib/faraday/error.rb'
-    - 'lib/faraday/utils.rb'
-    - 'lib/faraday/utils/headers.rb'
-    - 'script/generate_certs'
-    - 'spec/spec_helper.rb'
-
-# Offense count: 1
-# Cop supports --auto-correct.
-Performance/RedundantBlockCall:
-  Exclude:
-    - 'lib/faraday/request/multipart.rb'
-
-# Offense count: 3
-# Cop supports --auto-correct.
-Performance/StringReplacement:
-  Exclude:
-    - 'lib/faraday/encoders/flat_params_encoder.rb'
-    - 'lib/faraday/encoders/nested_params_encoder.rb'
-    - 'lib/faraday/request/basic_authentication.rb'
-
-# Offense count: 1
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: inline, group
-Style/AccessModifierDeclarations:
-  Exclude:
-    - 'lib/faraday/dependency_loader.rb'
-
-# Offense count: 9
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: prefer_alias, prefer_alias_method
-Style/Alias:
-  Exclude:
-    - 'lib/faraday/rack_builder.rb'
-    - 'lib/faraday/utils/headers.rb'
-    - 'lib/faraday/utils/params_hash.rb'
-
-# Offense count: 24
-# Cop supports --auto-correct.
-# Configuration parameters: EnforcedStyle.
-# SupportedStyles: always, conditionals
-Style/AndOr:
-  Exclude:
-    - 'lib/faraday/adapter/em_http.rb'
-    - 'lib/faraday/adapter/net_http.rb'
-    - 'lib/faraday/adapter/patron.rb'
-    - 'lib/faraday/connection.rb'
-    - 'lib/faraday/request/multipart.rb'
-    - 'lib/faraday/request/url_encoded.rb'
-    - 'lib/faraday/utils.rb'
-    - 'spec/support/helper_methods.rb'
-    - 'test/adapters/em_http_test.rb'
-    - 'test/helper.rb'
-
 # Offense count: 13
 # Cop supports --auto-correct.
 # Configuration parameters: EnforcedStyle, ProceduralMethods, FunctionalMethods, IgnoredMethods.
@@ -469,11 +392,10 @@ Style/NilComparison:
     - 'lib/faraday/encoders/flat_params_encoder.rb'
     - 'lib/faraday/encoders/nested_params_encoder.rb'
 
-# Offense count: 2
+# Offense count: 1
 # Cop supports --auto-correct.
 Style/Not:
   Exclude:
-    - 'lib/faraday/adapter/em_http.rb'
     - 'lib/faraday/response.rb'
 
 # Offense count: 7
diff --git a/lib/faraday/adapter/em_http.rb b/lib/faraday/adapter/em_http.rb
index fd2d5465..085fa72a 100644
--- a/lib/faraday/adapter/em_http.rb
+++ b/lib/faraday/adapter/em_http.rb
@@ -73,7 +73,7 @@ module Faraday
 
         # Reads out compression header settings from env into options
         def configure_compression(options, env)
-          if env[:method] == :get and not options[:head].key? 'accept-encoding'
+          if (env[:method] == :get) && !options[:head].key?('accept-encoding')
             options[:head]['accept-encoding'] = 'gzip, compressed'
           end
         end
@@ -168,7 +168,7 @@ module Faraday
       end
 
       def error_message(client)
-        client.error or 'request failed'
+        client.error || 'request failed'
       end
 
       def raise_error(msg)
diff --git a/lib/faraday/adapter/net_http.rb b/lib/faraday/adapter/net_http.rb
index be3ac4a3..84ee0cdd 100644
--- a/lib/faraday/adapter/net_http.rb
+++ b/lib/faraday/adapter/net_http.rb
@@ -39,7 +39,7 @@ module Faraday
       def call(env)
         super
         with_net_http_connection(env) do |http|
-          configure_ssl(http, env[:ssl]) if env[:url].scheme == 'https' and env[:ssl]
+          configure_ssl(http, env[:ssl]) if (env[:url].scheme == 'https') && env[:ssl]
           configure_request(http, env[:request])
 
           begin
@@ -103,7 +103,7 @@ module Faraday
       end
 
       def perform_request_with_wrapped_block(http, env, &block)
-        if :get == env[:method] and !env[:body]
+        if (:get == env[:method]) && !env[:body]
           # prefer `get` to `request` because the former handles gzip (ruby 1.9)
           request_via_get_method(http, env, &block)
         else
diff --git a/lib/faraday/adapter/patron.rb b/lib/faraday/adapter/patron.rb
index b9a10f19..00c10359 100644
--- a/lib/faraday/adapter/patron.rb
+++ b/lib/faraday/adapter/patron.rb
@@ -13,7 +13,7 @@ module Faraday
 
         session = ::Patron::Session.new
         @config_block.call(session) if @config_block
-        configure_ssl(session, env[:ssl]) if env[:url].scheme == 'https' and env[:ssl]
+        configure_ssl(session, env[:ssl]) if (env[:url].scheme == 'https') && env[:ssl]
 
         if (req = env[:request])
           session.timeout = session.connect_timeout = req[:timeout] if req[:timeout]
diff --git a/lib/faraday/connection.rb b/lib/faraday/connection.rb
index 99aa139c..6ee5741d 100644
--- a/lib/faraday/connection.rb
+++ b/lib/faraday/connection.rb
@@ -344,7 +344,7 @@ module Faraday
       @default_parallel_manager ||= begin
         adapter = @builder.adapter.klass if @builder.adapter
 
-        if adapter and adapter.respond_to?(:supports_parallel?) and adapter.supports_parallel?
+        if adapter && adapter.respond_to?(:supports_parallel?) && adapter.supports_parallel?
           adapter.setup_parallel_manager
         elsif block_given?
           yield
@@ -508,15 +508,15 @@ module Faraday
     #
     # @return [URI]
     def build_exclusive_url(url = nil, params = nil, params_encoder = nil)
-      url = nil if url.respond_to?(:empty?) and url.empty?
+      url = nil if url.respond_to?(:empty?) && url.empty?
       base = url_prefix
-      if url and base.path and base.path !~ /\/$/
+      if url && base.path && base.path !~ /\/$/
         base = base.dup
         base.path = base.path + '/' # ensure trailing slash
       end
       uri = url ? base + url : base
       uri.query = params.to_query(params_encoder || options.params_encoder) if params
-      uri.query = nil if uri.query and uri.query.empty?
+      uri.query = nil if uri.query && uri.query.empty?
       uri
     end
 
@@ -543,7 +543,7 @@ module Faraday
     # @return [void]
     # @api private
     def with_uri_credentials(uri)
-      if uri.user and uri.password
+      if uri.user && uri.password
         yield(Utils.unescape(uri.user), Utils.unescape(uri.password))
       end
     end
diff --git a/lib/faraday/dependency_loader.rb b/lib/faraday/dependency_loader.rb
index 84464bd8..f9df6094 100644
--- a/lib/faraday/dependency_loader.rb
+++ b/lib/faraday/dependency_loader.rb
@@ -2,8 +2,7 @@
 
 module Faraday
   module DependencyLoader
-    attr_accessor :load_error
-    private :load_error=
+    attr_reader :load_error
 
     # Executes a block which should try to require and reference dependent libraries
     def dependency(lib = nil)
@@ -26,5 +25,9 @@ module Faraday
       super
       subclass.send(:load_error=, load_error)
     end
+
+    private
+
+    attr_writer :load_error
   end
 end
diff --git a/lib/faraday/encoders/flat_params_encoder.rb b/lib/faraday/encoders/flat_params_encoder.rb
index 77709549..0bcc7cf2 100644
--- a/lib/faraday/encoders/flat_params_encoder.rb
+++ b/lib/faraday/encoders/flat_params_encoder.rb
@@ -56,7 +56,7 @@ module Faraday
         pair[0] = unescape(pair[0])
         pair[1] = true if pair[1].nil?
         if pair[1].respond_to?(:to_str)
-          pair[1] = unescape(pair[1].to_str.gsub(/\+/, ' '))
+          pair[1] = unescape(pair[1].to_str.tr('+', ' '))
         end
         if accu[pair[0]].kind_of?(Array)
           accu[pair[0]] << pair[1]
diff --git a/lib/faraday/encoders/nested_params_encoder.rb b/lib/faraday/encoders/nested_params_encoder.rb
index a03bdb84..ea2fcca1 100644
--- a/lib/faraday/encoders/nested_params_encoder.rb
+++ b/lib/faraday/encoders/nested_params_encoder.rb
@@ -87,7 +87,7 @@ module Faraday
 
         key, value = pair.split('=', 2)
         key = unescape(key)
-        value = unescape(value.gsub(/\+/, ' ')) if value
+        value = unescape(value.tr('+', ' ')) if value
 
         subkeys = key.scan(/[^\[\]]+(?:\]?\[\])?/)
         context = params
diff --git a/lib/faraday/error.rb b/lib/faraday/error.rb
index 80a42fef..890cc844 100644
--- a/lib/faraday/error.rb
+++ b/lib/faraday/error.rb
@@ -5,18 +5,18 @@ module Faraday
   class Error < StandardError
     attr_reader :response, :wrapped_exception
 
-    def initialize(ex, response = nil)
+    def initialize(exc, response = nil)
       @wrapped_exception = nil
       @response = response
 
-      if ex.respond_to?(:backtrace)
-        super(ex.message)
-        @wrapped_exception = ex
-      elsif ex.respond_to?(:each_key)
-        super("the server responded with status #{ex[:status]}")
-        @response = ex
+      if exc.respond_to?(:backtrace)
+        super(exc.message)
+        @wrapped_exception = exc
+      elsif exc.respond_to?(:each_key)
+        super("the server responded with status #{exc[:status]}")
+        @response = exc
       else
-        super(ex.to_s)
+        super(exc.to_s)
       end
     end
 
@@ -77,8 +77,8 @@ module Faraday
 
   # A unified client error for timeouts.
   class TimeoutError < ServerError
-    def initialize(ex = 'timeout', response = nil)
-      super(ex, response)
+    def initialize(exc = 'timeout', response = nil)
+      super(exc, response)
     end
   end
 
diff --git a/lib/faraday/options/env.rb b/lib/faraday/options/env.rb
index 08c57d14..b2c71a10 100644
--- a/lib/faraday/options/env.rb
+++ b/lib/faraday/options/env.rb
@@ -49,9 +49,11 @@ module Faraday
                           :ssl, :parallel_manager, :params, :response, :response_headers, :status,
                           :reason_phrase, :response_body)
 
+    # rubocop:disable Naming/ConstantName
     ContentLength = 'Content-Length'
     StatusesWithoutBody = Set.new [204, 304]
     SuccessfulStatuses = 200..299
+    # rubocop:enable Naming/ConstantName
 
     # A Set of HTTP verbs that typically send a body.  If no body is set for
     # these requests, the Content-Length header is set to 0.
diff --git a/lib/faraday/rack_builder.rb b/lib/faraday/rack_builder.rb
index 94deabf6..9d943a54 100644
--- a/lib/faraday/rack_builder.rb
+++ b/lib/faraday/rack_builder.rb
@@ -123,7 +123,7 @@ module Faraday
       @handlers.insert(index, handler)
     end
 
-    alias_method :insert_before, :insert
+    alias insert_before insert
 
     def insert_after(index, *args, &block)
       index = assert_index(index)
@@ -218,7 +218,7 @@ module Faraday
       !@adapter.nil?
     end
 
-    def is_adapter?(klass)
+    def is_adapter?(klass) # rubocop:disable Naming/PredicateName
       klass.ancestors.include?(Faraday::Adapter)
     end
 
diff --git a/lib/faraday/request/basic_authentication.rb b/lib/faraday/request/basic_authentication.rb
index e4a5fe24..adc5b8f4 100644
--- a/lib/faraday/request/basic_authentication.rb
+++ b/lib/faraday/request/basic_authentication.rb
@@ -11,7 +11,7 @@ module Faraday
     # @return [String] a Basic Authentication header line
     def self.header(login, pass)
       value = Base64.encode64([login, pass].join(':'))
-      value.gsub!("\n", '')
+      value.delete!("\n")
       super(:Basic, value)
     end
   end
diff --git a/lib/faraday/request/multipart.rb b/lib/faraday/request/multipart.rb
index 0c924773..37148222 100644
--- a/lib/faraday/request/multipart.rb
+++ b/lib/faraday/request/multipart.rb
@@ -24,9 +24,9 @@ module Faraday
     # @param env [Faraday::Env]
     def process_request?(env)
       type = request_type(env)
-      env.body.respond_to?(:each_key) and !env.body.empty? and (
-        (type.empty? and has_multipart?(env.body)) or
-        type == self.class.mime_type
+      env.body.respond_to?(:each_key) && !env.body.empty? && (
+        (type.empty? && has_multipart?(env.body)) ||
+        (type == self.class.mime_type)
       )
     end
 
@@ -34,7 +34,7 @@ module Faraday
     #
     # @param obj [Object]
     # @return [Boolean]
-    def has_multipart?(obj)
+    def has_multipart?(obj) # rubocop:disable Naming/PredicateName
       if obj.respond_to?(:each)
         (obj.respond_to?(:values) ? obj.values : obj).each do |val|
           return true if (val.respond_to?(:content_type) || has_multipart?(val))
@@ -76,7 +76,9 @@ module Faraday
         when Hash
           process_params(value, key, all, &block)
         else
+          # rubocop:disable Performance/RedundantBlockCall
           all << block.call(key, value)
+          # rubocop:enable Performance/RedundantBlockCall
         end
       end
     end
diff --git a/lib/faraday/request/url_encoded.rb b/lib/faraday/request/url_encoded.rb
index a1c5f3dd..1e0c9f93 100644
--- a/lib/faraday/request/url_encoded.rb
+++ b/lib/faraday/request/url_encoded.rb
@@ -37,7 +37,7 @@ module Faraday
     #                   urlencoded.
     def process_request?(env)
       type = request_type(env)
-      env.body and (type.empty? or type == self.class.mime_type)
+      env.body && (type.empty? || (type == self.class.mime_type))
     end
 
     # @param env [Faraday::Env]
diff --git a/lib/faraday/response/raise_error.rb b/lib/faraday/response/raise_error.rb
index c6ac900b..62751dcb 100644
--- a/lib/faraday/response/raise_error.rb
+++ b/lib/faraday/response/raise_error.rb
@@ -2,8 +2,8 @@
 
 module Faraday
   class Response::RaiseError < Response::Middleware
-    ClientErrorStatuses = 400...500
-    ServerErrorStatuses = 500...600
+    ClientErrorStatuses = 400...500 # rubocop:disable Naming/ConstantName
+    ServerErrorStatuses = 500...600 # rubocop:disable Naming/ConstantName
 
     def on_complete(env)
       case env[:status]
diff --git a/lib/faraday/utils.rb b/lib/faraday/utils.rb
index a1202df1..415f795e 100644
--- a/lib/faraday/utils.rb
+++ b/lib/faraday/utils.rb
@@ -19,13 +19,13 @@ module Faraday
 
     ESCAPE_RE = /[^a-zA-Z0-9 .~_-]/
 
-    def escape(s)
-      s.to_s.gsub(ESCAPE_RE) { |match|
+    def escape(str)
+      str.to_s.gsub(ESCAPE_RE) { |match|
         '%' + match.unpack('H2' * match.bytesize).join('%').upcase
       }.tr(' ', '+')
     end
 
-    def unescape(s) CGI.unescape s.to_s end
+    def unescape(str) CGI.unescape str.to_s end
 
     DEFAULT_SEP = /[&;] */n
 
@@ -86,7 +86,7 @@ module Faraday
     # Recursive hash update
     def deep_merge!(target, hash)
       hash.each do |key, value|
-        if Hash === value and Hash === target[key]
+        if (Hash === value) && (Hash === target[key])
           target[key] = deep_merge(target[key], value)
         else
           target[key] = value
diff --git a/lib/faraday/utils/headers.rb b/lib/faraday/utils/headers.rb
index 192a8676..de292c5d 100644
--- a/lib/faraday/utils/headers.rb
+++ b/lib/faraday/utils/headers.rb
@@ -49,47 +49,47 @@ module Faraday
       end
       KeyMap[:etag] = 'ETag'
 
-      def [](k)
-        k = KeyMap[k]
-        super(k) || super(@names[k.downcase])
+      def [](key)
+        key = KeyMap[key]
+        super(key) || super(@names[key.downcase])
       end
 
-      def []=(k, v)
-        k = KeyMap[k]
-        k = (@names[k.downcase] ||= k)
+      def []=(key, val)
+        key = KeyMap[key]
+        key = (@names[key.downcase] ||= key)
         # join multiple values with a comma
-        v = v.to_ary.join(', ') if v.respond_to? :to_ary
-        super(k, v)
+        val = val.to_ary.join(', ') if val.respond_to?(:to_ary)
+        super(key, val)
       end
 
-      def fetch(k, *args, &block)
-        k = KeyMap[k]
-        key = @names.fetch(k.downcase, k)
+      def fetch(key, *args, &block)
+        key = KeyMap[key]
+        key = @names.fetch(key.downcase, key)
         super(key, *args, &block)
       end
 
-      def delete(k)
-        k = KeyMap[k]
-        if (k = @names[k.downcase])
-          @names.delete k.downcase
-          super(k)
+      def delete(key)
+        key = KeyMap[key]
+        if (key = @names[key.downcase])
+          @names.delete key.downcase
+          super(key)
         end
       end
 
-      def include?(k)
-        @names.include? k.downcase
+      def include?(key)
+        @names.include? key.downcase
       end
 
-      alias_method :has_key?, :include?
-      alias_method :member?, :include?
-      alias_method :key?, :include?
+      alias has_key? include?
+      alias member? include?
+      alias key? include?
 
       def merge!(other)
         other.each { |k, v| self[k] = v }
         self
       end
 
-      alias_method :update, :merge!
+      alias update merge!
 
       def merge(other)
         hash = dup
diff --git a/lib/faraday/utils/params_hash.rb b/lib/faraday/utils/params_hash.rb
index 62f61ae3..d0a8626d 100644
--- a/lib/faraday/utils/params_hash.rb
+++ b/lib/faraday/utils/params_hash.rb
@@ -20,9 +20,9 @@ module Faraday
         super(convert_key(key))
       end
 
-      alias_method :has_key?, :include?
-      alias_method :member?, :include?
-      alias_method :key?, :include?
+      alias has_key? include?
+      alias member? include?
+      alias key? include?
 
       def update(params)
         params.each do |key, value|
@@ -30,7 +30,7 @@ module Faraday
         end
         self
       end
-      alias_method :merge!, :update
+      alias merge! update
 
       def merge(params)
         dup.update(params)
diff --git a/script/generate_certs b/script/generate_certs
index 32393fc2..e9379c13 100755
--- a/script/generate_certs
+++ b/script/generate_certs
@@ -11,12 +11,12 @@ $shell = ARGV.include? '-s'
 
 # Adapted from WEBrick::Utils. Skips cert extensions so it
 # can be used as a CA bundle
-def create_self_signed_cert(bits, cn, comment)
+def create_self_signed_cert(bits, cname, comment)
   rsa = OpenSSL::PKey::RSA.new(bits)
   cert = OpenSSL::X509::Certificate.new
   cert.version = 2
   cert.serial = 1
-  name = OpenSSL::X509::Name.new(cn)
+  name = OpenSSL::X509::Name.new(cname)
   cert.subject = name
   cert.issuer = name
   cert.not_before = Time.now
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index dd9fc71c..219fb010 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -120,10 +120,10 @@ end
 
 # Extends RSpec DocumentationFormatter to hide skipped tests.
 module FormatterOverrides
-  def example_pending(_)
+  def example_pending(_arg)
   end
 
-  def dump_pending(_)
+  def dump_pending(_arg)
   end
 
   RSpec::Core::Formatters::DocumentationFormatter.prepend self
diff --git a/spec/support/helper_methods.rb b/spec/support/helper_methods.rb
index 04755b4b..79ed993b 100644
--- a/spec/support/helper_methods.rb
+++ b/spec/support/helper_methods.rb
@@ -15,7 +15,7 @@ module Faraday
         if @features.nil?
           superclass.on_feature(name, &block) if superclass.respond_to?(:on_feature)
         else
-          yield if block_given? and @features.include?(name)
+          yield if block_given? && @features.include?(name)
         end
       end
 
diff --git a/test/adapters/em_http_test.rb b/test/adapters/em_http_test.rb
index 5bb917bb..90463852 100644
--- a/test/adapters/em_http_test.rb
+++ b/test/adapters/em_http_test.rb
@@ -15,7 +15,7 @@ module Adapters
         conn = create_connection request: { bind: { host: host } }
         assert_equal host, conn.options[:bind][:host]
       end
-    end unless jruby? and ssl_mode?
+    end unless jruby? && ssl_mode?
     # https://github.com/eventmachine/eventmachine/issues/180
 
     def test_custom_adapter_config
diff --git a/test/helper.rb b/test/helper.rb
index 18c0fe9e..d9c718b2 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -36,7 +36,7 @@ module Faraday
 
     # Returns an object that responds to `host` and `port`.
     def live_server
-      live_server? and @@live_server
+      live_server? && @@live_server
     end
   end
 
@@ -59,11 +59,11 @@ module Faraday
     end
 
     def self.jruby?
-      defined? RUBY_ENGINE and 'jruby' == RUBY_ENGINE
+      defined? RUBY_ENGINE && ('jruby' == RUBY_ENGINE)
     end
 
     def self.rbx?
-      defined? RUBY_ENGINE and 'rbx' == RUBY_ENGINE
+      defined? RUBY_ENGINE && ('rbx' == RUBY_ENGINE)
     end
 
     def self.ruby_22_plus?