Oxford English Dictionaryto make love [after Old Occitan far amor (13th cent.), Middle French, French faire l'amour (16th cent.; 1622 with reference to sexual intercourse), or Italian far l'amore].
(a) To pay amorous attention; to court, woo. Frequently with to. Also in extended use. Now somewhat archaic.
1768 L. Sterne Sentimental Journey I. 79 You have been making love to me all this while.
1948 W. S. Maugham Catalina (1958) ii. 18 Her lover Diego no longer came to the window at night to make love to her through the iron grille.
1972 B. Everitt Cold Front v. 38 ‘Are we conversing or making love?’‥ ‘Let's go into the slow lane for a minute.’
(b) orig. U.S. To engage in sexual intercourse, esp. considered as an act of love. Freq. with to, with.
Historic examples:1950 M. Peake Gormenghast xxix. 173 One of the Carvers made love to her and she had a baby.
1971 Daily Tel. 15 Jan. 17/1 Couples who make love frequently are more likely to have sons than those who do so less often.
1999 T. Parsons Man & Boy (2000) ii. 19 We were making love on the floor—or the futon, as Gina called it.