Green’s Dictionary of Slang

1. (US Und.) to throw out; to get rid of.

1950

Goldin et al. DAUL 63/2: Duke out. To get rid of; to declare out; to ease out.

2. (US) to knock out.

1990

(con. early 1950s) J. Ellroy L.A. Confidential 33: The Mex he’d duked out.