source: 40 Day Pokemon ChallengeDay 24: Favorite Poison typeA smilin GIF | Find, Make & Share Gfycat GIFs

1. offensive to the senses, especially through having a disgusting smell or taste or being unpleasantly soiled:

(ひどく)汚い, 不潔な〈水･空気など〉; 不快な; まずい

e.g. a foul odor

e.g. his foul breath.

informal very disagreeable or unpleasant:

｟主に英｠ 〖通例名詞の前で〗悪い, ひどい, 不愉快な〈機嫌･気分など〉

e.g. the news had put Michelle in a foul mood.

2. wicked or immoral:

不正な, 悪い;｟主に文｠ 邪悪な, 卑劣な

e.g. murder most foul.

(of language) obscene or profane.

〖通例名詞の前で〗失礼な, 汚い〈言葉など〉

done contrary to the rules of a sport:

〖名詞の前で〗〘スポーツ〙 反則の; ファウルの 〘野球〙

e.g. a foul tackle.

3. containing or charged with noxious matter; polluted:

くさい, 腐敗した, 汚染した

e.g. foul, swampy water.

predicative (foul with) clogged or choked with:

〈パイプなどが〉詰まった

e.g. the land was foul with weeds.

Nautical (of a rope or anchor) entangled.

〈ロープなどが〉もつれた, からんだ

(of a ship's bottom) encrusted with algae, barnacles, or other marine growth.

(船底に)フジツボ［海草］が付いた

Printing (of a first copy or proof) defaced by corrections.

4. (of the weather) wet and stormy.

｟主に英｠ 〈天候が〉荒れた, 悪い, 暴風雨の

Sailing (of wind or tide) opposed to one's desired course.

逆風の

1. (in sports) an unfair or invalid stroke or piece of play, especially one involving interference with an opponent.

反則, ファウル

a collision or entanglement in riding, rowing, or running.

衝突

short for foul ball.

〘野球〙 ファウル(foul ball)

2. informal, dated a disease in the feet of cattle:

e.g. he was indeed suffering from foul of the foot.

unfairly; contrary to the rules.

不正に; 反則して

(in sports) in foul territory:

e.g. if a batter hits a bunt foul with two strikes, he is out.

verb with object

1. make foul or dirty; pollute:

｟かたく｠ 〈人が〉〈場所〉を汚す; 〈物〉を汚くする, 汚染する(up)

e.g. factories that fouled the atmosphere.

disgrace or dishonor.

〈名声〉をけがす

(of an animal) make (something) dirty with excrement:

〈動物が〉〈場所〉をふんで汚す

e.g. make sure that your pet never fouls the sidewalk.

(foul oneself) (of a person) defecate involuntarily.

2. (in sports) commit a foul against (an opponent).

〘スポーツ〙 〈相手〉に反則行為をする; …を反則で妨害する

Baseball hit a foul ball:

〘野球〙 〈ボール〉をファウルする

e.g. Carter fouled into the glove of Boggs.

3. (of a ship) collide with or interfere with the passage of (another).

〈船が〉…と衝突する

cause (a cable, anchor, or other object) to become entangled or jammed:

〈機械･車が〉〈ロープなど〉をからませる(up)

e.g. watch out for driftwood which might foul up the engine

〈ロープなどが〉からまる(up).

e.g. no object : we feared the anchor would foul in the heavy grasses.

do something damaging or harmful to oneself or one's own interests.

see fall.

make a mistake with or spoil something:

e.g. leaders should admit when they completely foul things up.

Basketball be put out of the game for exceeding the permitted number of fouls.

Baseball (of a batter) be made out by hitting a foul ball that is caught by an opposing player:

e.g. Wilson has never fouled out against this young pitcher.

foully |ˈfou(l)lē| adverb

foulness |ˈfoulnəs| noun

Old English fūl, of Germanic origin; related to Old Norse fúll ‘foul’, Dutch vuil ‘dirty’, and German faul ‘rotten, lazy’, from an Indo-European root shared by Latin pus, Greek puos ‘pus’, and Latin putere ‘to stink’.