An act that violates the rules of a sport.

Polish: faul

Hit a foul ball.

Roget 276: give an impetus etc. n.; impel, push; start, give a start to, set going; drive, urge, boom; thrust, prod, foin [Fr.]; cant; elbow, shoulder, jostle, justle^†, hustle, hurtle, shove, jog, jolt, encounter; run against, bump against, butt against; knock one's head against, run one's head against; impinge; boost [U.S.]; bunt, carom, clip y; fan, fan out; jab, plug [Slang].    strike, knock, hit, tap, rap, slap, flap, dab, pat, thump, beat, blow, bang, slam, dash; punch, thwack, whack; hit hard, strike hard; swap, batter, dowse^†, baste; pelt, patter, buffet, belabor; fetch one a blow; poke at, pink, lunge, yerk^†; kick, calcitrate^†; butt, strike at etc. (attack) 716; whip etc. (punish) 972.    come into a collision, enter into collision; collide; sideswipe; foul; fall foul of, run foul of; telescope.    throw etc. (propel) 284.    ... show more

Make impure.

synonyms: contaminate, pollute.

Dutch: verontreinigen, vervuilen

Become or cause to become obstructed.

synonyms: back up, choke, choke off, clog, clog up, congest.

Dutch: ophopen

Commit a foul; break the rules.

Spot, stain, or pollute.

synonyms: befoul, defile, maculate.

Make unclean.

Become soiled and dirty.

Dutch: vervuilen

Highly offensive; arousing aversion or disgust.

synonyms: disgustful, disgusting, distasteful, loathly, loathsome, repellant, repellent, repelling, revolting, skanky, wicked, yucky ... show more.

Roget 940: dishonest, dishonorable; unconscientious, unscrupulous; fraudulent etc. 545; knavish; disgraceful etc. (disreputable) 974; wicked etc. 945.    false-hearted, disingenuous; unfair, one-sided; double, double-hearted, double-tongued, double-faced; timeserving^†, crooked, tortuous, insidious, Machiavelian, dark, slippery; fishy; perfidious, treacherous, perjured.    infamous, arrant, foul, base, vile, ignominious, blackguard.    contemptible, unrespectable, abject, mean, shabby, little, paltry, dirty, scurvy, scabby, sneaking, groveling, scrubby, rascally, pettifogging; beneath one.    low-minded, low-thoughted^†; base-minded.    undignified, indign^†; unbecoming, unbeseeming^†, unbefitting; derogatory, degrading; infra dignitatem [Lat.], beneath one's dignity; ungentlemanly, ungentlemanlike; unknightly^†, unchivalric^†, unmanly, unhandsome; recreant, inglorious.    corrupt, venal; debased, mongrel.    faithless, of bad faith, false, unfaithful, disloyal; untrustworthy; trustless, trothless^†; lost to shame, dead to honor; barratrous.    ... show more

Roget 846: ugly, ugly as sin, ugly as a toad, ugly as a scarecrow, ugly as a dead monkey; plain, bald (unadorned) 849; homely; ordinary, unornamental^†, inartistic; unsightly, unseemly, uncomely, unlovely; unshapely; sightless, seemless^†; not fit to be seen; unbeauteous^†, unbeautiful; beautiless^†, semibeautiful; shapeless etc. (amorphous) 241.    misshapen, misproportioned^†; monstrous; gaunt etc. (thin) 203; dumpy etc. (short) 201; curtailed of its fair proportions; ill-made, ill-shaped, ill-proportioned; crooked etc. (distorted) 243; hard featured, hard visaged; ill-favored, hard-favored, evil-favored; ill-looking; unprepossessing, unattractive, uninviting, unpleasing.    graceless, inelegant; ungraceful, ungainly, uncouth, stiff; rugged, rough, gross, rude, awkward, clumsy, slouching, rickety; gawky; lumping, lumpish^†; lumbering; hulky^†, hulking; unwieldy.    squalid, haggard; grim, grim faced, grim visaged; grisly, ghastly; ghost like, death like; cadaverous, grewsome^†, gruesome.    frightful, hideous, odious, uncanny, forbidding; repellant, repulsive, repugnant, grotesque, bizarre; grody [Coll.], grody to the max [Coll.]; horrid, horrible; shocking etc. (painful) 830.    foul etc. (dirty) 653; dingy etc. (colorless) 429; gaudy etc. (color) 428; disfigured etc. v.; discolored.    ... show more

Roget 945: vicious; sinful; sinning etc. v.; wicked, iniquitous, immoral, unrighteous, wrong, criminal; naughty, incorrect; unduteous^†, undutiful.    unprincipled, lawless, disorderly, contra bonos mores [Lat.], indecorous, unseemly, improper; dissolute, profligate, scampish; unworthy; worthless; desertless^†; disgraceful, recreant; reprehensible, blameworthy, uncommendable; discreditable, disreputable; Sadistic.    base, sinister, scurvy, foul, gross, vile, black, grave, facinorous^†, felonious, nefarious, shameful, scandalous, infamous, villainous, of a deep dye, heinous; flagrant, flagitious; atrocious, incarnate, accursed.    Mephistophelian, satanic, diabolic, hellish, infernal, stygian, fiendlike^†, hell-born, demoniacal, devilish, fiendish.    miscreated^†, misbegotten; demoralized, corrupt, depraved.    evil-minded, evil-disposed; ill-conditioned; malevolent etc. 907; heartless, graceless, shameless, virtueless; abandoned, lost to virtue; unconscionable; sunk in iniquity, lost in iniquity, steeped in iniquity.    incorrigible, irreclaimable, obdurate, reprobate, past praying for; culpable, reprehensible etc. (guilty) 947.    unjustifiable; indefensible, inexcusable; inexpiable, unpardonable, irremissible^†.    weak, frail, lax, infirm, imperfect; indiscrete; demoralizing, degrading.    ... show more

Polish: obrzydły, ohydny, wstrętny, obrzydliwy, obmierzły

Offensively malodorous:
— A foul odor.

synonyms: fetid, foetid, foul-smelling, funky, ill-scented, noisome, smelly, stinking.

Roget 649: hurtful, harmful, scathful^†, baneful, baleful; injurious, deleterious, detrimental, noxious, pernicious, mischievous, full of mischief, mischief-making, malefic, malignant, nocuous, noisome; prejudicial; disserviceable^†, disadvantageous; wide-wasting.    unlucky, sinister; obnoxious; untoward, disastrous.    oppressive, burdensome, onerous; malign etc. (malevolent) 907.    corrupting etc. (corrupt) etc. 659; virulent, venomous, envenomed, corrosive; poisonous etc. (morbific) 657^†; deadly etc. (killing) 361; destructive etc. (destroying) 162; inauspicious etc. 859.    bad, ill, arrant, as bad as bad can be, dreadful; horrid, horrible; dire; rank, peccant, foul, fulsome; rotten, rotten at the core.    vile, base, villainous; mean etc. (paltry) 643; injured &c.; deteriorated etc. 659; unsatisfactory, exceptionable indifferent; below par etc. (imperfect) 651; illcontrived, ill-conditioned; wretched, sad, grievous, deplorable, lamentable; pitiful, pitiable, woeful etc. (painful) 830.    evil, wrong; depraved etc. 945; shocking; reprehensible etc. (disapprove) 932.    hateful, hateful as a toad; abominable, detestable, execrable, cursed, accursed, confounded; damned, damnable; infernal; diabolic etc. (malevolent) 907.    unadvisable etc. (inexpedient) 647; unprofitable etc. (useless) 645; incompetent etc. (unskillful) 699; irremediable etc. (hopeless) 859.    ... show more

Roget 398: odorous, odoriferous; smelling, reeking, foul-smelling, strong-scented; redolent, graveolent^†, nidorous^†, pungent; putrid, foul.    [Relating to the sense of smell] olfactory, quick-scented.    ... show more

Polish: smrodliwy

Violating accepted standards or rules:
— Used foul means to gain power.

synonyms: cheating, dirty, unsporting, unsportsmanlike.

of a baseball Not hit between the foul lines.

of a manuscript Defaced with changes:
— Foul (or dirty) copy.

synonyms: dirty, marked-up.

Characterized by obscenity:
— Foul language.

synonyms: cruddy, filthy, nasty, smutty.

Roget 653: dirty, filthy, grimy; unclean, impure; soiled etc. v.; not to be handled with kid gloves; dusty, snuffy^†, smutty, sooty, smoky; thick, turbid, dreggy; slimy; mussy [U.S.].    slovenly, untidy, messy, uncleanly.    [of people] unkempt, sluttish, dowdy, draggle-tailed; uncombed.    unscoured^†, unswept^†, unwiped^†, unwashed, unstrained, unpurified^†; squalid; lutose^†, slammocky^†, slummocky^†, sozzly^†.    nasty, coarse, foul, offensive, abominable, beastly, reeky, reechy^†; fetid etc. 401.    [of rotting living matter] decayed, moldy, musty, mildewed, rusty, moth-eaten, mucid^†, rancid, weak, bad, gone bad, etercoral^†, lentiginous^†, touched, fusty, effete, reasty^†, rotten, corrupt, tainted, high, flyblown, maggoty; putrid, putrefactive, putrescent, putrefied; saprogenic, saprogenous^†; purulent, carious, peccant; fecal, feculent; stercoraceous^†, excrementitious^†; scurfy, scurvy, impetiginous^†; gory, bloody; rotting etc. v.; rotten as a pear, rotten as cheese.    crapulous etc. (intemperate) 954^†; gross etc. (impure in mind) 961; fimetarious^†, fimicolous^†.    ... show more

Disgustingly dirty; filled or smeared with offensive matter:
— A foul pond.

synonyms: filthy, nasty.

Polish: plugawy

Especially of a ship's lines etc:
— With its sails afoul.
— A foul anchor.

synonyms: afoul, fouled.