deadening vs boring

deadening and boring both are nouns.

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

As adjectives, deadening and boring are synonyms defined as:

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

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

deadening (noun)	boring (noun)
the act of making something futile and useless (as by routine)	the act of drilling a hole in the earth in the hope of producing petroleum
	the act of drilling

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