Green’s Dictionary of Slang

(US teen) a man who tries to pick up girls in the street.

1922		Davenport Democrat and Leader (IA) 28 May 32/2–3: So we made the blow and gave ’em the air, and then crashed a jazz-garden where a flock of sub-chasers and dumb-doras were rattlin’ their dogs.
1922		L.A. Times 4 May section II 4: Herewith another installment of snappy younger generation slang just broadcast from eastern points, where it has its origin: Subchaser: A man who tries to pick up girls on the street.