WordWeb Online

1. Hinder or prevent (the efforts, plans, or desires) of
   "What ultimately frustrated every challenger was Ruth's amazing September surge";
   - thwart, queer, spoil, scotch, foil, cross, baffle, bilk
    
2. Harass persistently in cruel or annoying way
   "The children frustrated the stuttering teacher";
   - torment, rag, bedevil, crucify, dun
    
3. Deprive of courage or hope; take away hope from; cause to feel discouraged
   - discourage

Derived forms: frustrates, frustrated, frustrating

Type of: beset, chevvy [non-standard], chevy, chivvy, chivy, forbid, foreclose, forestall, harass, harry, hassle, molest, plague, preclude, prevent, provoke