From WordNet (r) 3.0 (2006):
foul
adj 1: highly offensive; arousing aversion or disgust; "a
disgusting smell"; "distasteful language"; "a loathsome
disease"; "the idea of eating meat is repellent to me";
"revolting food"; "a wicked stench" [syn: disgusting,
disgustful, distasteful, foul, loathly,
loathsome, repellent, repellant, repelling,
revolting, skanky, wicked, yucky]
2: offensively malodorous; "a foul odor"; "the kitchen smelled
really funky" [syn: fetid, foetid, foul, foul-
smelling, funky, noisome, smelly, stinking, ill-
scented]
3: violating accepted standards or rules; "a dirty fighter";
"used foul means to gain power"; "a nasty unsporting serve";
"fined for unsportsmanlike behavior" [syn: cheating(a),
dirty, foul, unsporting, unsportsmanlike]
4: (of a baseball) not hit between the foul lines [ant: fair]
5: (of a manuscript) defaced with changes; "foul (or dirty)
copy" [syn: dirty, foul, marked-up]
6: characterized by obscenity; "had a filthy mouth"; "foul
language"; "smutty jokes" [syn: cruddy, filthy, foul,
nasty, smutty]
7: disgustingly dirty; filled or smeared with offensive matter;
"as filthy as a pigsty"; "a foul pond"; "a nasty pigsty of a
room" [syn: filthy, foul, nasty]
8: especially of a ship's lines etc; "with its sails afoul"; "a
foul anchor" [syn: afoul(ip), foul, fouled]
n 1: an act that violates the rules of a sport
v 1: hit a foul ball
2: make impure; "The industrial wastes polluted the lake" [syn:
pollute, foul, contaminate]
3: become or cause to become obstructed; "The leaves clog our
drains in the Fall"; "The water pipe is backed up" [syn:
clog, choke off, clog up, back up, congest,
choke, foul] [ant: unclog]
4: commit a foul; break the rules
5: spot, stain, or pollute; "The townspeople defiled the river
by emptying raw sewage into it" [syn: foul, befoul,
defile, maculate]
6: make unclean; "foul the water"
7: become soiled and dirty