foot soldier vs marcher

foot soldier and marcher both are nouns.

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

As nouns, foot soldier and marcher are synonyms defined as:

Other synonyms of foot soldier include footslogger, infantryman.

foot soldier (noun)	marcher (noun)
fights on foot with small arms	fights on foot with small arms
an assistant subject to the authority or control of another	walks with regular or stately step
	an inhabitant of a border district