Green’s Dictionary of Slang

(US) an aware, wise person.

1902		T.A. Dorgan in Zwilling TAD Lex. (1993) 45: Joe Hip/For Congress/Son of old man Hip.
1942		Berrey & Van Den Bark Amer. Thes. Sl. 352: Joe Hep, sharp cat, sharpy.
1941		D. Burley N.Y. Amsterdam Star-News 7 June 13: joe q. hipp, The Stroll’s Last Dip.
1944		D. Burley Orig. Hbk of Harlem Jive 15: Pop, I’m tops, replied Joe Hipp.