1. Rotten, contaminated, or dirty: Sally asked, "Have you ever noticed how badly the foul eggs can smell when they have been around too long?"
2. Unfavorable; contrary to the rules of a competition or sport: Charles has a reputation for being a foul player.

The player committed a foul play when he tripped the other soccer player.

After Bill was suspended from the football game, he was asked why he committed a foul play so often, in fact at the beginning of just about every new game.

Birds collectively; a large edible bird; such as, a chicken, a turkey, a duck, etc.: The Bradley family roasted a fowl for their Thanksgiving meal.