fundamental vs important

fundamental is a noun but important is not a noun.

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

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

fundamental (adjective)	important (adjective)
being or involving basic facts or principles	of great significance or value
serving as an essential component	of extreme importance; vital to the resolution of a crisis
far-reaching and thoroughgoing in effect especially on the nature of something	important in effect or meaning
	having or suggesting a consciousness of high position
	having authority or ascendancy or influence