skilled workman vs worker

skilled workman and worker both are nouns.

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

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

skilled workman (noun)	worker (noun)
a worker who has acquired special skills	sterile member of a colony of social insects that forages for food and cares for the larvae
	a person who works at a specific occupation
	a member of the working class (not necessarily employed)
	a person who acts and gets things done