foul spot, stain, or pollute

foul make impure

foul become or cause to become obstructed

foul especially of a ship''s lines etc

foul disgustingly dirty; filled or smeared with offensive matter

foul characterized by obscenity

foul thoroughly unpleasant

foul violating accepted standards or rules

foul offensively malodorous

foul (of a manuscript) defaced with changes

foul highly offensive; arousing aversion or disgust