diff --git a/lib/kaui.rb b/lib/kaui.rb
index 0f5e2f27..abbaa585 100644
--- a/lib/kaui.rb
+++ b/lib/kaui.rb
@@ -203,14 +203,3 @@ def self.config
     }
   end
 end
-
-# ruby-1.8 compatibility
-module Kernel
-  # rubocop:disable Style/ArgumentsForwarding
-  def define_singleton_method(*args, &)
-    class << self
-      self
-    end.send(:define_method, *args, &)
-  end
-  # rubocop:enable Style/ArgumentsForwarding
-end