marcher vs infantryman

marcher and infantryman both are nouns.

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

As nouns, marcher and infantryman are synonyms defined as:

Other synonyms of marcher include foot soldier, footslogger.

marcher (noun)	infantryman (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