Green’s Dictionary of Slang

(orig. US) unaware, unsophisticated, ignorant; thus as n., one who lacks sophistication.

1938		‘Idioms of the Present-Day American Negro’ in AS XIII:4 Dec. 314/1: UNHIPPED. Opposite of hipped.
1938		Flash! (Wash., D.C.) 21 Feb. 11/1: unhep — Any individual who impresses one as not being a person who really knows just what it is all about, very briefly a tenderfoot or greenhorn.
1939		Herbert & Spencer Jitterbug Jamboree Song Book 33: unhip: not familiar, not wise.
1939		D. Burley N.Y. Amsterdam News 30 Sept. 16: A certain ‘hip’ reporter was ‘unhipped’ when he fell for a cutie and came up [...] minus 25 bucks.
1940		Pittsburgh Courier (PA) 27 Apr. 7/6: If you dig one of those weird and unhep chics, don’t play the castle strong.
1941		N.Y. Age 10 May 9/6: Mow, don’t you Unhips feel too blue, I too once wrote as bum as you.
1946		Mezzrow & Wolfe Really the Blues 89: The routine was so unhip she couldn’t have made it up.
1958		Mad mag. May–June 20: My label, baby doll, is unhip to me.
1958		Hughes & Bontemps Book of Negro Folklore 488: unhip: A square. She’s so unhipped it’s a shame.
1961		T. Taylor Baron’s Court All Change (2011) 22: Tito Burns’ Bebop Spoken Here (which is now very unhip, but at least it was a start).
1968		Realist Nov. 15/1: There are a lot of those slang words [...] charva means fuck. Eye magazine printed it ‘charver.’ Eye magazine . . . So unhip!
1976		Cab Calloway Of Minnie the Moocher and Me 71: We had come out of the Midwest playing old-time, unhip, novelty tunes.
1986		B. Geldof Is That It? 99: I thought he was very unhip.
2001		(con. 1945–6) P. Doyle Devil’s Jump (2008) 100: Strictly for unhep squares, dad. Get hep to the rebop, pop.