irritate vs rub

irritate is not a noun while rub is a noun.

Word	Noun	Adjective	Verb	Adverb
irritate	No	No	Yes	No
rub	Yes	No	Yes	No

As verbs, rub is a hyponym of irritate; that is, rub is a word with a more specific, narrower meaning than irritate:

Other hyponyms of irritate include chafe, fret, gall, itch, scratch.

irritate (noun)	rub (noun)
	the act of rubbing or wiping
	an unforeseen obstacle

irritate (verb)	rub (verb)
excite to an abnormal condition, or chafe or inflame	move over something with pressure
excite to some characteristic action or condition, such as motion, contraction, or nervous impulse, by the application of a stimulus	cause friction
cause annoyance in; disturb, especially by minor irritations	scrape or rub as if to relieve itching