(1):

(v. t.) To corrupt, debase, or make impure by an admixture of a foreign or a baser substance; as, to adulterate food, drink, drugs, coin, etc.

(2):

(a.) Debased by the admixture of a foreign substance; adulterated; spurious.

(3):

(a.) Tainted with adultery.

(4):

(v. i.) To commit adultery.

(5):

(v. t.) To defile by adultery.