Green’s Dictionary of Slang

man-eater n.

[orig. naut. use, a particularly disciplinarian officer, ult. SE, a man-eating tiger]

1. a watchman, a constable.

[UK]T. Brown Amusements Serious and Comical in Works (1744) III 22: The man-eaters, that stood not far off, seeking whom they might devour [...] I have been too lately in their clutches to desire any more dealings with them.

2. a swindler.

[US]Ely’s Hawk & Buzzard (NY) Sept. 14 n.p.: There now resides in our good city [...] one of the bold man-eaters [...] alias, Doctor Quick [...] he swears that if any of his bad deeds are exposed [...] he will bung the two eyes of poor Johannas .
[US]Wood & Goddard Dict. Amer. Sl. 46: shark. an expert; also a gouger, man-eater, as in loan-shark.

3. (Anglo-Ind.) a horse that tends to bite people.

[UK]Sporting Mag. Nov. 31 : The larger horses from Hindoostan [...] are leggy, under-limbed, and, as far as vice goes, regular man-eaters .
[Ind]Civil & Milit. Gaz. (Lahore) 19 June 1/3: Girofle, while being trained last year [...] developed a most violent temper, and came to be universally regarded as a ‘man-eater’.
[US]Van Loan ‘Chivalry in Carbon County’ in Score by Innings (2004) 320: They ain’t none of ’em what you might call man-eaters, but they’re feerocious enough for New Jersey.

4. a sexually predatory woman.

[Aus]Dead Bird (Sydney) 27 Sept. 6/3: A dandy crowd of genuine sports, [...] mashers and man-eaters rubbing shoulders in all directions.
[Aus]E. Dyson Fact’ry ’Ands 136: To Spats’ Beauties she was always Porline or The Man-Eater.
[UK]‘Bartimeus’ ‘The Wooing of Mouldy Jakes’ in Awfully Big Adventure 38: I’m not going to face those man-eaters alone.
[US]J. Black You Can’t Win (2000) 54: Wha do you think she did, kid — the big man-eater!
[US]B. Hecht Gaily, Gaily 92: I’ve always wanted to love one of those creamy-skinned man-eaters.
[UK]C. Dexter Last Bus to Woodstock 179: Mary indeed! Dumpy, freckled, little man-eater!
[US](con. 1940s) C. Bram Hold Tight (1990) 187: You afraid bad man-eating Lena’s gonna throw herself at you.
[UK]Guardian G2 22 July 11: As if Lulu was an aggressive man-eater.
[US]J. Stahl I, Fatty 52: Lilly-Bell, a big blond [sic] maneater.

5. a tough overseer, employer, etc.

[UK]N. Lucas Autobiog. of a Thief 201: The chief officer [...] was a ‘man-eater,’ they said, and hated stowaways.
[UK]B. Lubbock Bully Hayes 59: It took a hell of a man-eater to tackle Bully Hayes.

6. a homosexual man; a fellator.

[US]B. Rodgers Queens’ Vernacular 52: fellator [...] maneater.
[US]Maledicta III:2 231: A sod or a bugger need not be a pedicator any more than a cocksucker in America need be a maneater, a head artist, a flute-player or a fellator.
[US]H. Max Gay (S)language 27: Maneater—gay who performs fellatio often and/or well.

In derivatives

man-eating (adj.)

1. devoted to fellatio.

[US]F. Hilaire Thanatos 176: You’re a come-drunk, man-eating fairy!

2. of a woman, seen as aggressively disliking males.

[US]K. Tomlinson ‘Thicker Than Water’ in C. Rhatigan and N. Bird (eds) Pulp Ink 2 [ebook] He turned on the charm. Totally wasted on the man-eating bitch.