WordWeb Online

1. An urge to do or say something that might be better left undone or unsaid
   "he felt a compulsion to babble on about the accident";
   - irresistible impulse
    
2. An irrational motive for performing trivial or repetitive actions, even against your will
   "her compulsion to wash her hands repeatedly";
   - obsession
    
3. Using force to cause something to occur
   "though pressed into rugby under compulsion I began to enjoy the game";
   - coercion

Derived forms: compulsions

Type of: causation, irrational impulse, irrational motive

Encyclopedia: Compulsion