fusilier vs foot soldier

fusilier and foot soldier both are nouns.

Word	Noun	Adjective	Verb	Adverb
fusilier	Yes	No	No	No
foot soldier	Yes	No	No	No

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

fusilier: (formerly) a British infantryman armed with a light flintlock musket
foot soldier: fights on foot with small arms

Other hypernyms of fusilier include footslogger, infantryman, marcher.

fusilier (noun)	foot soldier (noun)
(formerly) a British infantryman armed with a light flintlock musket	fights on foot with small arms
	an assistant subject to the authority or control of another