Foul

Obstructed, entangled, dirty or otherwise not clear for its intended purpose.

The precise meaning depends on context. A fouled propeller or anchor is entangled; a foul bottom is covered with marine growth; foul ground contains obstructions that make anchoring or fishing hazardous; and a foul berth does not provide adequate room to lie safely.

The word can also describe adverse conditions, such as a foul wind, or contact that breaches a racing rule. Because it has several distinct nautical uses, the object or condition described should normally accompany the word.