lobsterman vs skilled workman

lobsterman and skilled workman both are nouns.

Word	Noun	Adjective	Verb	Adverb
lobsterman	Yes	No	No	No
skilled workman	Yes	No	No	No

As nouns, skilled workman is a hypernym of lobsterman; that is, skilled workman is a word with a broader meaning than lobsterman:

Other hypernyms of lobsterman include skilled worker, trained worker.

lobsterman (noun)	skilled workman (noun)
a person whose occupation is catching lobsters	a worker who has acquired special skills