aquanaut vs trained worker

aquanaut and trained worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
aquanaut	Yes	No	No	No
trained worker	Yes	No	No	No

As nouns, trained worker is a hypernym of aquanaut; that is, trained worker is a word with a broader meaning than aquanaut:

aquanaut: a skilled worker who can live in underwater installations and participate in scientific research
trained worker: a worker who has acquired special skills

Other hypernyms of aquanaut include skilled worker, skilled workman.

aquanaut (noun)	trained worker (noun)
an underwater swimmer equipped with a face mask and foot fins and either a snorkel or an air cylinder	a worker who has acquired special skills
a skilled worker who can live in underwater installations and participate in scientific research