infantryman vs marcher

infantryman and marcher both are nouns.

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

As nouns, infantryman and marcher are synonyms defined as:

Other synonyms of infantryman include foot soldier, footslogger.

infantryman (noun)	marcher (noun)
fights on foot with small arms	fights on foot with small arms
	walks with regular or stately step
	an inhabitant of a border district