WordWeb Online

1. (law) 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
   "Their behaviour stultified the boss's hard work";
   - cripple

Derived forms: stultifying, stultifies, stultified

Type of: blackguard, demonstrate, establish, guy, jest at, laugh at, make fun, poke fun, prove, rib [informal], ridicule, roast [informal], shew [Brit, archaic], show, weaken