paramour

A lover, especially a lover of a person who is married to someone else.

With love; in love; as a lover.

A lover, of either sex; a wooer.

A lover, of either sex, in a bad sense; one who takes the place of a husband or wife without legal right: the only sense of the word now in use.

Love, as between the sexes; gallantry.

To love; be in love with; woo.

By or with love, esp. the love of the sexes; — sometimes written as two words.

A lover, of either sex; a wooer or a mistress (formerly in a good sense, now only in a bad one); one who takes the place, without possessing the rights, of a husband or wife; — used of a man or a woman.

Love; gallantry.

An illicit lover, either male or female.