unfriendliness vs unfriendly

unfriendliness is a noun but unfriendly is not a noun.

Word	Noun	Adjective	Verb	Adverb
unfriendliness	Yes	No	No	No
unfriendly	No	Yes	No	No

unfriendliness (noun)	unfriendly (noun)
an unfriendly disposition
dislike experienced as an absence of friendliness

unfriendliness (adjective)	unfriendly (adjective)
	not disposed to friendship or friendliness
	not easy to understand or use
	very unfavorable to life or growth
	not friendly