foremost vs first

foremost is not a noun while first is a noun.

Word	Noun	Adjective	Verb	Adverb
foremost	No	Yes	No	Yes
first	Yes	Yes	No	Yes

As adjectives, foremost and first are synonyms defined as:

Other synonyms of foremost include world-class.

As adverbs, foremost and first are synonyms defined as:

As adverbs, foremost and first are synonyms defined as:

Other synonyms of foremost include first of all, first off, firstly.

foremost (noun)	first (noun)
	the fielding position of the player on a baseball team who is stationed at first of the bases in the infield (counting counterclockwise from home plate)
	the lowest forward gear ratio in the gear box of a motor vehicle; used to start a car moving
	an honours degree of the highest class
	the first element in a countable series
	the first or highest in an ordering or series
	the time at which something is supposed to begin

foremost (adjective)	first (adjective)
ranking above all others	preceding all others in time or space or degree
situated closest to the bow	highest in pitch or chief among parts or voices or instruments or orchestra sections
preceding all others in spatial position	ranking above all others
	serving to begin
	serving to set in motion

foremost (adverb)	first (adverb)
prominently forward	before anything else
before anything else	prominently forward
	the initial time
	before another in time, space, or importance