Green’s Dictionary of Slang

1. get out! go away!

1964		J. Gelber On Ice 7: It’s eighty-six. Get out of here!
1975		L. Dills CB Slanguage 36: Eighty-Six: back off.
1983		National Lampoon Aug. 91: Eighty-six, Jack [HDAS].

2. (US campus) no!

1981

Eble Campus Sl. Fall 3: eighty-six – no, nix.