mindless vs mindlessness

mindless is not a noun while mindlessness is a noun.

Word	Noun	Adjective	Verb	Adverb
mindless	No	Yes	No	No
mindlessness	Yes	No	No	No

mindless (noun)	mindlessness (noun)
	the trait of acting rashly and without prudence
	total lack of meaning or ideas

mindless (adjective)	mindlessness (adjective)
not mindful or attentive
devoid of intelligence or thought
lacking the thinking capacity characteristic of a conscious being
requiring little mental effort
not marked by the use of reason