lockmaster vs trained worker

lockmaster and trained worker both are nouns.

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

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

Other hypernyms of lockmaster include skilled worker, skilled workman.

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