Green’s Dictionary of Slang

connaught (ranger) n.

a stranger.

1950		P. Hoskins No Hiding Place! 190/1: Connaught Rangers. Strangers.
1970		R. Fabian Anatomy of Crime 192: I was slipping down the frog and toad (road) and linked up with a connaught ranger (stranger) [...] Blow me if the connaught didn’t scarper.