clumsy vs clumsiness

clumsy is not a noun while clumsiness is a noun.

Word	Noun	Adjective	Verb	Adverb
clumsy	No	Yes	No	No
clumsiness	Yes	No	No	No

clumsy (noun)	clumsiness (noun)
	the carriage of someone whose movements and posture are ungainly or inelegant
	the inelegance of someone stiff and unrelaxed (as by embarrassment)
	unskillfulness resulting from a lack of training

clumsy (adjective)	clumsiness (adjective)
lacking grace in movement or posture
not elegant or graceful in expression
showing lack of skill or aptitude
difficult to handle or manage especially because of shape