Green’s Dictionary of Slang

1. to accelerate a car.

1940

R.L. Bellem ‘Death’s Passport’ in Goodstone Pulps (1970) 117/2: He blooped that sedan up to seventy from a standing start.

2. to hit, to punch.

1952

N.Y. Daily Mirror 8 July 24: [Prizefighter] Turner blooped a bolo to the heart [W&F].