guardsman vs soldier

guardsman and soldier both are nouns.

Word	Noun	Adjective	Verb	Adverb
guardsman	Yes	No	No	No
soldier	Yes	No	Yes	No

As nouns, soldier is a hypernym of guardsman; that is, soldier is a word with a broader meaning than guardsman:

guardsman: a soldier who is a member of a unit called `the guard' or `guards'
soldier: an enlisted man or woman who serves in an army

guardsman (noun)	soldier (noun)
a soldier who is a member of a unit called `the guard' or `guards'	a wingless sterile ant or termite having a large head and powerful jaws adapted for defending the colony
	an enlisted man or woman who serves in an army

guardsman (verb)	soldier (verb)
	serve as a soldier in the military