central vs primal

central is a noun but primal is not a noun.

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

As adjectives, central and primal are synonyms defined as:

Other synonyms of central include cardinal, fundamental, key.

central (noun)	primal (noun)
a workplace that serves as a telecommunications facility where lines from telephones can be connected together to permit communication

central (adjective)	primal (adjective)
in or near a center or constituting a center; the inner area	having existed from the beginning; in an earliest or original stage or state
serving as an essential component	serving as an essential component