casualness vs casual

casualness is a noun but casual is not a noun.

Word	Noun	Adjective	Verb	Adverb
casualness	Yes	No	No	No
casual	No	Yes	No	No

casualness (noun)	casual (noun)
a casual manner
The state of coming without regularity; of being occasional or incidental.

casualness (adjective)	casual (adjective)
	hasty and without attention to detail; not thorough
	not showing effort or strain
	occurring on a temporary or irregular basis
	marked by blithe unconcern
	appropriate for ordinary or routine occasions
	occurring or appearing or singled out by chance
	natural and unstudied
	characterized by a feeling of irresponsibility
	without or seeming to be without plan or method; offhand