uninteresting vs deadening

uninteresting is not a noun while deadening is a noun.

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

uninteresting (noun)	deadening (noun)
	the act of making something futile and useless (as by routine)

uninteresting (adjective)	deadening (adjective)
arousing no interest or attention or curiosity or excitement	so lacking in interest as to cause mental weariness
characteristic or suggestive of an institution especially in being uniform or dull or unimaginative