irksome vs boring

irksome is not a noun while boring is a noun.

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

As adjectives, irksome and boring are synonyms defined as:

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

irksome (noun)	boring (noun)
	the act of drilling a hole in the earth in the hope of producing petroleum
	the act of drilling

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