essential vs of import

essential is a noun but of import is not a noun.

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

essential (noun)	of import (noun)
anything indispensable

essential (adjective)	of import (adjective)
basic and fundamental	of great significance or value
defining rights and duties as opposed to giving the rules by which rights and duties are established
being or relating to or containing the essence of a plant etc
of the greatest importance
absolutely necessary; vitally necessary