basic vs 1st

basic is a noun but 1st is not a noun.

Word	Noun	Adjective	Verb	Adverb
basic	Yes	Yes	No	No
1st	No	Yes	No	No

basic (noun)	1st (noun)
(usually in the plural) a necessary commodity for which demand is constant

basic (adjective)	1st (adjective)
pertaining to or constituting a base or basis	preceding all others in time or space or degree
of or denoting or of the nature of or containing a base
reduced to the simplest and most significant form possible without loss of generality
serving as a base or starting point