Dulling

verb

1. To render dull; to remove or blunt an edge or something that was sharp.

   "Years of misuse have dulled the tools."

2. To soften, moderate or blunt; to make dull, stupid, or sluggish; to stupefy.

   "He drinks to dull the pain."

3. To lose a sharp edge; to become dull.

   "A razor will dull with use."

4. To render dim or obscure; to sully; to tarnish.