Green’s Dictionary of Slang

1. (US black/Harlem) a housekeeper.

1944

D. Burley Orig. Hbk of Harlem Jive 12: I nixes my pad, drops the twister on the keep, and collars a light broom down the cruncher to the lushpad on the three pointer.

2. a mistress (she is ‘kept’).

1959

A. Burgess Beds in the East (1972) 531: ‘Oh, God, yes, when you think of the five-dollar doses in the Park, and those bloody Chinese keeps: gimme, gimme, gimme.’.

3. (US) a barman [SAmE barkeep].

1966

M. Rumaker Exit 3 and Other Stories 38: ‘Hey, keep, two beers,’ shouted the sailor. [Ibid.] 104: We got you, keepie. Don’t get sore.