unlikeliness vs unlikely

unlikeliness is a noun but unlikely is not a noun.

Word	Noun	Adjective	Verb	Adverb
unlikeliness	Yes	No	No	No
unlikely	No	Yes	No	No

unlikeliness (noun)	unlikely (noun)
the improbability of a specified outcome

unlikeliness (adjective)	unlikely (adjective)
	has little chance of being the case or coming about
	not likely to be true or to occur or to have occurred
	having a probability too low to inspire belief