Etymology: Middle English, from Old English fūl; akin to Old High German fūl rotten, Latin pus pus, putēre to stink, Greek pyon pus
Date: before 12th century
a. offensive to the senses ; loathsome
b. filled or covered with offensive matter
2. full of dirt or mud
a. morally or spiritually odious ; detestable <a foul crime> b. notably unpleasant or distressing ; wretched, horrid <in a foul mood> 4. obscene, abusive <foul language> 5. a. being wet and stormy b. obstructive to navigation <a foul tide> 6. dialect British homely, ugly 7. a. treacherous, dishonorable <fair means or foul> b. constituting an infringement of rules in a game or sport <a foul blow in boxing> 8. containing marked-up corrections <a foul manuscript> <foul proofs> 9. encrusted, clogged, or choked with a foreign substance <the chimney was foul and smoked badly> 10. being odorous and impure ; polluted <foul air> 11. placed in a situation that impedes physical movement ; entangled 12. being outside the foul lines in baseball Synonyms: see dirty • foully adverb • foulness noun II. noun Date: before 12th century 1. archaic something foul 2. an entanglement or collision especially in angling or sailing 3. a. an infringement of the rules in a game or sport b. free throw 4. foul ball III. verb Date: before 12th century intransitive verb 1. to become or be foul: as a. decompose, rot b. to become encrusted, clogged, or choked with a foreign substance c. to become entangled or come into collision 2. to commit a violation of the rules in a sport or game 3. to hit a foul ball transitive verb 1. to make foul: as a. to make dirty ; pollute b. to tangle or come into collision with c. to encrust with a foreign substance <a ship's bottom fouled with barnacles> d. obstruct, block 2. dishonor, discredit 3. to commit a foul against 4. to hit (a baseball) foul IV. adverb Date: 13th century in a foul manner ; so as to be foul
New Collegiate Dictionary. 2001.