foul / foul/ • adj. 1. offensive to the senses, esp. through having a disgusting smell or taste or being unpleasantly soiled: a foul odor his foul breath. ∎ inf. very disagreeable or unpleasant: the news had put Michelle in a foul mood. ∎  (of the weather) wet and stormy. ∎  Sailing (of wind or tide) opposed to one's desired course.2. wicked or immoral: murder most foul. ∎  (of language) obscene or profane. ∎  done contrary to the rules of a sport: a foul tackle.3. containing or charged with noxious matter; polluted: foul, swampy water. ∎  (foul with) clogged or choked with: the land was foul with weeds. ∎  Naut. (of a rope or anchor) entangled. ∎  (of a ship's bottom) encrusted with algae, barnacles, or other marine growth. ∎ Printing (of a first copy or proof) defaced by corrections.• n. 1. (in sports) an unfair or invalid stroke or piece of play, esp. one involving interference with an opponent. ∎  a collision or entanglement in riding, rowing, or running. ∎ short for foul ball.2. inf., dated a disease in the feet of cattle.• adv. unfairly; contrary to the rules. ∎  (in sports) in foul territory: if a batter hits a bunt foul with two strikes, he is out.• v. [tr.] 1. make foul or dirty; pollute: factories that fouled the atmosphere. ∎  disgrace or dishonor. ∎  (of an animal) make (something) dirty with excrement: 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). ∎ Baseball hit a foul ball: Carter fouled into the glove of Boggs.3. (of a ship) collide with or interfere with the passage of (another). ∎  cause (a cable, anchor, or other object) to become entangled or jammed: watch out for driftwood which might foul up the engine. ∎  [intr.] become entangled in this way.PHRASES: fall foul ofsee fall.foul one's (own) nest do something damaging or harmful to oneself or one's own interests.PHRASAL VERBS: foul out 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: Wilson has never fouled out against this young pitcher.foul something up (or foul up) make a mistake with or spoil something: leaders should admit when they completely foul things up.DERIVATIVES: foul·ly / ˈfou(l)lē/ adv.foul·ness n.ORIGIN: 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.’