underlying vs basic

underlying is not a noun while basic is a noun.

Word	Noun	Adjective	Verb	Adverb
underlying	No	Yes	No	No
basic	Yes	Yes	No	No

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

underlying (adjective)	basic (adjective)
being or involving basic facts or principles	pertaining to or constituting a base or basis
in the nature of something though not readily apparent	of or denoting or of the nature of or containing a base
located beneath or below	reduced to the simplest and most significant form possible without loss of generality
	serving as a base or starting point