WordWeb Online

1. Offensive or even (of persons) malicious
   "in a nasty mood"; "a nasty accident"; "Will he say nasty things at my funeral?";
   - awful
    
2. Exasperatingly difficult to handle or circumvent
   "a nasty problem";
   - tight
    
3. Characterized by obscenity
   "had a nasty mouth";
   - filthy, foul, smutty
    
4. Disgustingly dirty; filled or smeared with offensive matter
   "a nasty pigsty of a room";
   - filthy, foul, cruddy [informal]

Derived forms: nastiest, nastier

See also: cruddy [informal], difficult, dirty, filthy, grotty [Brit, informal], hard, hateful, lousy [informal], mean, nastiness, soiled, unclean, unpleasant

Antonym: nice

Encyclopedia: Nasty, brutish, and short