of import vs fundamental

of import is not a noun while fundamental is a noun.

Word	Noun	Adjective	Verb	Adverb
of import	No	Yes	No	No
fundamental	Yes	Yes	No	No

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

of import (adjective)	fundamental (adjective)
of great significance or value	being or involving basic facts or principles
	serving as an essential component
	far-reaching and thoroughgoing in effect especially on the nature of something