Anaphrodisiac

An anaphrodisiac (also antaphrodisiac or antiaphrodisiac) is something that quells or blunts the libido. It is the opposite of an aphrodisiac, something that enhances sexual appetite. The word anaphrodisiac comes from the Greek privative prefix ἀν-, denoting negation, and aphrodisiac, from the Greek goddess of love, Aphrodite.