Green’s Dictionary of Slang

O’Malley n.

[use of Irish surname O’Malley as a generic]

a police officer, usu. male.

[US]P. Atoon Rap Dict. 🌐 O’Malley (n) An Irish name, pointing to the traditionally strong represented Irish in the LAPD. Gonna put a slug in captain O’Malley – Cypress Hill (We ain’t goin’ out like that).