bullet vs hummer

bullet and hummer both are nouns.

Word	Noun	Adjective	Verb	Adverb
bullet	Yes	No	No	No
hummer	Yes	No	No	No

As nouns, bullet and hummer are synonyms defined as:

Other synonyms of bullet include fastball, heater, smoke.

bullet (noun)	hummer (noun)
(baseball) a pitch thrown with maximum velocity	(baseball) a pitch thrown with maximum velocity
a projectile that is fired from a gun	a singer who produces a tune without opening the lips or forming words
a high-speed passenger train