great vs important

great is a noun but important is not a noun.

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

great (noun)	important (noun)
a person who has achieved distinction and honor in some field

great (adjective)	important (adjective)
excellent	of great significance or value
in an advanced stage of pregnancy	of extreme importance; vital to the resolution of a crisis
uppercase	important in effect or meaning
remarkable or out of the ordinary in degree or magnitude or effect	having or suggesting a consciousness of high position
of major significance or importance	having authority or ascendancy or influence
relatively large in size or number or extent; larger than others of its kind