uninteresting vs interestingness

uninteresting is not a noun while interestingness is a noun.

Word	Noun	Adjective	Verb	Adverb
uninteresting	No	Yes	No	No
interestingness	Yes	No	No	No

uninteresting (noun)	interestingness (noun)
	the power of attracting or holding one's attention (because it is unusual or exciting etc.)

uninteresting (adjective)	interestingness (adjective)
arousing no interest or attention or curiosity or excitement
characteristic or suggestive of an institution especially in being uniform or dull or unimaginative