WordWeb Online

1. Inspiring scornful pity
   "how ridiculous an ardent and unsuccessful wooer can be especially if he is getting on in years";
   - pathetic, silly
    
2. Incongruous; inviting ridicule
   "her conceited assumption of universal interest in her rather dull children was ridiculous";
   - absurd, cockeyed, derisory, idiotic, laughable, ludicrous, nonsensical, preposterous
    
3. Broadly or extravagantly humorous; resembling farce
   "the wild ridiculous exuberance of a clown";
   - farcical, ludicrous

See also: daft, dumb, foolish, humorous, humourous [Brit, Cdn, non-standard], stupid, undignified

Encyclopedia: Ridiculous