Meaning of “bang” - Learner’s Dictionary

bang

verb [ I, T ] uk us /bæŋ/
NOISE

B2 to make a loud noise, especially by hitting something against something hard:

We heard the door bang.
Ben banged his fist on the desk.
HIT

to hit part of your body against something hard:

Ted fell and banged his head.
→ See also be banging your head against a brick wall

(Definition of “bang verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)