lockman vs skilled worker

lockman and skilled worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
lockman	Yes	No	No	No
skilled worker	Yes	No	No	No

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

Other hypernyms of lockman include skilled workman, trained worker.

lockman (noun)	skilled worker (noun)
a worker in charge of a lock (on a canal)	a worker who has acquired special skills