stultify

Verb

  1. prove to be of unsound mind or demonstrate someone’s incompetence; “nobody is legally allowed to stultify himself”
  2. cause to appear foolish; “He stultified himself by contradicting himself and being inconsistent”
  3. deprive of strength or efficiency; make useless or worthless; “This measure crippled our efforts”; “Their behavior stultified the boss’s hard work”