rifleman vs soldier

rifleman and soldier both are nouns.

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

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

rifleman (noun)	soldier (noun)
a soldier whose weapon is a rifle	a wingless sterile ant or termite having a large head and powerful jaws adapted for defending the colony
someone skilled in the use of a rifle	an enlisted man or woman who serves in an army

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