wearisome vs deadening

wearisome is not a noun while deadening is a noun.

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

As adjectives, wearisome and deadening are synonyms defined as:

wearisome and deadening: so lacking in interest as to cause mental weariness

Other synonyms of wearisome include boring, dull, ho-hum, irksome, slow, tedious, tiresome.

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

wearisome (adjective)	deadening (adjective)
so lacking in interest as to cause mental weariness	so lacking in interest as to cause mental weariness