Grossly offensive to the senses; of a filthy or noxious character or quality; noisome; disgusting: as, foul matter or exudations; a foul smell; foul breath.2. Of a harmful or mischievous character; causing trouble or annoyance; obnoxious; obstructive; clogging: as, foul weeds; foul weather; a foul wind.Affected by noisome or defiling matter; in a filthy state or condition; unclean; dirty; turbid; defiled: as, foul clothing; foul den; a foul stream.Affected by harmful matter or things; obstructed by anything fixed or attached; clogged; choked: as, a foul garden (one full of weeds); a foul chimney (one choked with soot); the ship's bottom is foul (clogged with seaweeds or barnacles); the channel has a foul bottom (one cumbered by rocks, wrecks, or the like).Clogged or impeded as by collision or entanglement; in a state of obstructing contact or involvement: with of before the obstructive object: as, the ship is foul of a rock or of another ship; a rope or an anchor is foul from being jammed, entangled, or clogged in any way.Contrary to or violating rule or established usage; done, acting, or acted upon improperly; irregular; disorderly; unfair: as, a foul blow or stroke: a foul player or fighter; a foul attack. See foul play, below.Grossly offensive or loathsome in a moral sense; manifesting, or prompted or actuated by, base or vicious feeling; vile; odious; shameful; revolting: as, foul thoughts or actions; foul language; a foul slander, murder, conspiracy, etc.; a foul slanderer or conspirator.Extremely bad as to effect or result; unfavorable; unlucky; pernicious; distressing: us, a foul accident; a foul prospect or omen.Coarse; common; of little value.Ill-favored; ugly; homely.To attack; make an assault upon. See afoul.n. The act of fouling, colliding, or otherwise impeding due motion or progress; specifically, in a contest of any kind, a violation of the governing rules.n. In base-ball, a hit which makes the ball land outside the lines from home to first or to third base continued indefinitely; a foul ball or a foul hit. See base-ball.n. An ulcer in a cow's foot; a disease that produces ulcers.In a foul manner.To make foul, in any sense; befoul.Nautical, to entangle.To become foul or dirty: as, a gun. fouls from long use.Nautical, to come into collision, as two boats; become entangled or clogged: as, the rope fouled; the block fouled.In base-ball, to strike a foul balln. An obsolete spelling of fowl.