primal vs fundamental

primal is not a noun while fundamental is a noun.

Word	Noun	Adjective	Verb	Adverb
primal	No	Yes	No	No
fundamental	Yes	Yes	No	No

As adjectives, primal and fundamental are synonyms defined as:

Other synonyms of primal include cardinal, central, key.

primal (noun)	fundamental (noun)
	the lowest tone of a harmonic series
	any factor that could be considered important to the understanding of a particular business

primal (adjective)	fundamental (adjective)
having existed from the beginning; in an earliest or original stage or state	being or involving basic facts or principles
serving as an essential component	serving as an essential component
	far-reaching and thoroughgoing in effect especially on the nature of something