1 offensive, loathsome, disgusting, obnoxious, revolting, repulsive, repellent, repugnant, sickening, nauseous, nauseating, nasty, beastly, Archaic fulsome:
The bartender makes a foul concoction he swears will cure a hangover.
2 filthy, unclean, nasty, polluted, putrid, putrescent, putrefactive or putrefacient, defiled, soiled, spoiled, rotten, decayed, decomposed, rancid, soured, turned, tainted, mouldy, impure, adulterated, contaminated, stale, bad, Brit off:
The hamburger place was closed when public health inspectors found foul food in the freezer.
3 smelly, stinking, noisome, fetid or foetid, rank, evil-smelling, foul-smelling, malodorous, musty, mephitic, graveolent:
A foul odour emanated from the cabinet.
4 wicked, vile, bad, base, abominable, low, sordid, iniquitous, evil, flagitious, atrocious, monstrous, nefarious, sinful, immoral, amoral, vicious, villainous, scandalous, infamous, dishonourable, shameful, disgraceful, ignominious; detestable:
They were finally brought to justice for their foul deeds.
5 dirty, obscene, filthy, profane, scatological, gross, smutty, foul-mouthed, blue, licentious, salacious, lewd, indecent, improper, coarse, uncouth, vulgar, rude, scurrilous, rough, indelicate, immodest, risqué, off colour, suggestive, bawdy, ribald, Rabelaisian, Fescennine, US raw, Slang raunchy:
My mother forbids my reading books containing foul language.
6 abusive, offensive, affronting, insulting, disparaging, maligning, thersitical, calumnious or calumniatory, aspersive, slanderous, defamatory, libellous, denigrating, derogatory, deprecatory or deprecative, depreciatory or depreciative, denunciatory or denunciative, derisory, derisive, scornful, belittling, fulminous, objurgatory or objurgative, vituperative, invective:
Keep your foul tongue to yourself.
7 dishonest, unfair, unjust, unsportsmanlike, dishonourable, fraudulent, underhand(ed), double-dealing, two-faced, corrupt, venal, dirty, treacherous, perfidious, traitorous, unscrupulous, Colloq crooked, shady, Slang chiefly Brit bent:
Thrupp will get his way by fair means or foul.
8 nasty, dangerous, rough, disagreeable, unfavourable, sloppy, stormy, adverse; windy, blustery; snowy, sleety, wet, rainy:
We ran into a spot of foul weather at Dover.
9 obstructed, blocked, choked, stopped (up), plugged (up), clogged (up):
The drain is foul with all that rubbish.
10 tangled, entangled, caught, ensnared, enmeshed, snarled:
A foul anchor is a common nautical symbol.
11 illegal, prohibited, forbidden, interdicted, not fair; dirty:
In boxing a hit below the belt is a foul blow.
12 dirty, pollute, sully, befoul, defile, soil, contaminate, adulterate, taint:
Effluent from the factory was fouling the river.
13 tangle, entangle, catch, snare, ensnare, enmesh, snag, snarl, jam, twist:
We can't hoist the mainsail because the halyard is fouled.
14 disgrace, dishonour, sully, taint, besmirch, defile, soil, stain, smear, tarnish, blacken, denigrate, debase, degrade, abase, demean, disparage, defame, derogate, asperse, devaluate, depreciate, vitiate, belittle, discredit, bring or call into disrepute:
That act of treachery will foul the family name for generations.
15 obstruct, block, choke, stop or plug or clog (up):
Dead leaves fouled the downpipe.
16 foul up.
(a) See def. 13.
(b) mismanage, mishandle, botch, bungle, make a mess (of), mess up, spoil, ruin, Colloq muff, Brit throw a spanner in(to) (the works), US throw a monkey wrench into (the machinery); Slang muck up, goof (up), blow, screw up, louse up, Chiefly Brit bugger (up), US and Canadian snafu:
Give him a chance and he's sure to foul up.
She fouled up my hi-fi.
17 violation, infringement, infraction, illegality:
The Rangers' forward has already been charged with two fouls.
18 afoul, in conflict, in trouble, in violation:
Curshaw has fallen foul of the law again.