ignorantness vs ignorant

ignorantness is a noun but ignorant is not a noun.

Word	Noun	Adjective	Verb	Adverb
ignorantness	Yes	No	No	No
ignorant	No	Yes	No	No

ignorantness (noun)	ignorant (noun)
ignorance (especially of orthodox beliefs)

ignorantness (adjective)	ignorant (adjective)
	unaware because of a lack of relevant information or knowledge
	uneducated in the fundamentals of a given art or branch of learning; lacking knowledge of a specific field
	uneducated in general; lacking knowledge or sophistication