banger vs firecracker

banger and firecracker both are nouns.

Word	Noun	Adjective	Verb	Adverb
banger	Yes	No	No	No
firecracker	Yes	No	No	No

As nouns, banger and firecracker are synonyms defined as:

banger and firecracker: firework consisting of a small explosive charge and fuse in a heavy paper casing

Other synonyms of banger include cracker.

banger (noun)	firecracker (noun)
firework consisting of a small explosive charge and fuse in a heavy paper casing	firework consisting of a small explosive charge and fuse in a heavy paper casing
(British informal) pork sausage