fusilier vs infantryman

fusilier and infantryman both are nouns.

Word	Noun	Adjective	Verb	Adverb
fusilier	Yes	No	No	No
infantryman	Yes	No	No	No

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

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

Other hypernyms of fusilier include foot soldier, footslogger, marcher.

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