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.’

foul foul anchor an anchor that has become entangled with a rope or cable, as the badge of the British Admiralty.
foul one's own nest do something damaging or harmful to oneself or one's own interests. From the proverbial condemnation, current in English since the early 15th century and before that in Latin, of a person who vilifies their own country or family, it is an ill bird that fouls its own nest.
foul play criminal or violent behaviour, in particular when resulting in another's death.

foul grossly offensive to the senses; opp. of clean OE.; opp. of fair ME. OE. fūl = OS., OHG. fūl (Du. vuil dirty, G. faul rotten, unsound, lazy), ON. fúll, Goth. fūls stinking :- Gmc *fūlaz, f. *fū̆- :- IE. *pū̆-, as in L. pūs PUS, putridus PUTRID, etc.