bomb vs bombing

bomb and bombing both are nouns.

Word	Noun	Adjective	Verb	Adverb
bomb	Yes	No	Yes	No
bombing	Yes	No	No	No

bomb (noun)	bombing (noun)
an explosive device fused to explode under specific conditions	an attack by dropping bombs
strong sealed vessel for measuring heat of combustion	the use of bombs for sabotage; a tactic frequently used by terrorists
an event that fails badly or is totally ineffectual

bomb (verb)	bombing (verb)
throw bombs at or attack with bombs
fail to get a passing grade