rocket engineer vs engineer

rocket engineer and engineer both are nouns.

Word	Noun	Adjective	Verb	Adverb
rocket engineer	Yes	No	No	No
engineer	Yes	No	Yes	No

As nouns, engineer is a hypernym of rocket engineer; that is, engineer is a word with a broader meaning than rocket engineer:

rocket engineer: an engineer who builds and tests rockets
engineer: a person who uses scientific knowledge to solve practical problems

Other hypernyms of rocket engineer include applied scientist, technologist.

rocket engineer (noun)	engineer (noun)
an engineer who builds and tests rockets	a person who uses scientific knowledge to solve practical problems
	the operator of a railway locomotive

rocket engineer (verb)	engineer (verb)
	plan and direct (a complex undertaking)
	design as an engineer