foul (Verb) — (baseball) hit a foul ball.
foul (Verb) — Make impure in a bad way; make something harmful, especially by the addition of some unwanted substance. ex. "The industrial wastes fouled the lake"
foul (Verb) — Become or cause to become obstructed. ex. "The leaves foul our drains in the Fall"
foul (Verb) — Commit a foul; break the rules.
foul (Verb) — Spoil Spot, stain, or pollute. ex. "The townspeople fouled the river by emptying raw sewage into it"
foul (Verb) — Make unclean. ex. "foul the water"
foul (Verb) — Become soiled and dirty.
foul (Adjective) — Highly offensive; arousing aversion or disgust. ex. "a foul smell"
foul (Adjective) — Offensively malodorous. ex. "a foul odour" ex. "a foul-smelling odour"
foul (Adjective) — Violating accepted standards or rules. ex. "used foul means to gain power"
foul (Adjective) — (of a manuscript) defaced with changes. ex. "foul copy"
foul (Adjective) — Characterized by obscenity. ex. "foul language"
foul (Adjective) — Disgustingly dirty; filled or smeared with offensive matter. ex. "a foul pond"
foul (Adjective) — (nautical) not having freedom of motion due to collision or entanglement; entangled. ex. "a foul anchor"
foul (Adjective) — (of a baseball) not hit between the foul lines.
foul (Noun) — (sport) an act that violates the rules of a sport.