Green’s Dictionary of Slang

1. (US) a pimp [euph.].

1842		Wkly Rake (NY) 30 July n.p.: There are twenty thousand wantons in this city, each of whom boasts a man devoted entirely to her service, and who is termed a lover. These young men [...] by some uncontrollable circumstance have taken to this means of living, from which they are unable to escape.
1843		Whip & Satirist of NY & Brooklyn (NY) 21 Jan. n.p.: To these ‘lovers,’ and their women, I would caution them to beware, as I am acquainted with some dark and hellish deeds.
1849		G. Thompson Venus in Boston 98: [S]everal courtezans of the ordinary class were lounging about, or indolently conversing with a few intimate male friends, who were probably their private lovers, or pimps.
1872		E. Crapsey Nether Side of NY 142: Lost women [...] burdened almost without exception with ‘lovers’ who despoil them of the pittance they receive for moral and physical death [...] no class needs so much of pity.
1904		Number 1500 Life In Sing Sing 250: Lover. A man who receives support from a prostitute.
1936		Mencken Amer. Lang. (4th edn) n.p.: A pimp is a . . . McGimp, fish and shrimp, lover, Latin lover and many others.
1949		Monteleone Criminal Sl. (rev. edn).

2. (orig. US) an affectionate general term of address, though no actual love affair need be implied.

1911		G. Stratton-Porter Harvester 194: ‘Hello, lover!’ cried Doctor Carey as the Harvester entered the office. ‘Are you married yet?’ .
1947		B. Schulberg Harder They Fall (1971) 91: Hello, lover.
1953		J. Thompson Alcoholics (1993) 31: Murph, lover, you are going to help me, aren’t you?
1963		A.E. Morgan Six-Eleven (1966) 184: Want some, lover?
1967		M.S. Brookins ‘Aspiration’, in Kochman Rappin’ and Stylin’ Out (1972) 382: Hi young lover, what’s happening?
1994		G. Pelecanos Shoedog 149: Randolph [...] looked over at Constantine. ‘You gonna be all right, lover?’ ‘I’ll be all right’.

3. (US Und.) a rapist or bigamist [euph.].

1950

Goldin et al. DAUL 130/1: Lover. 1. (P) (Ironic) A rapist; a bigamist; a seductionist; any criminal offender against the person of a woman.