Webster's Revised Unabridged Dictionary · 1913

Paramour

Paramour , noun

[French par amour, lit., by or with love. See 2d Par, and Amour.]

1.
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.
The seducer appeared with dauntless front, accompanied by his paramour — Macaulay
2.
Love; gallantry. [Obsolete]
For paramour and jollity. — Chaucer

Paramour , adverb

By or with love, esp. the love of the sexes; -- sometimes written as two words. [Obsolete]
For par amour, I loved her first ere thou. — Chaucer

Also: Paramours