hydrogen-bomb vs bomb

hydrogen-bomb is not a noun while bomb is a noun.

Word	Noun	Adjective	Verb	Adverb
hydrogen-bomb	No	No	Yes	No
bomb	Yes	No	Yes	No

As verbs, bomb is a hypernym of hydrogen-bomb; that is, bomb is a word with a broader meaning than hydrogen-bomb:

Other hypernyms of hydrogen-bomb include bombard.

hydrogen-bomb (noun)	bomb (noun)
	an explosive device fused to explode under specific conditions
	strong sealed vessel for measuring heat of combustion
	an event that fails badly or is totally ineffectual

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