irritate vs physiology

irritate is not a noun while physiology is a noun.

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

irritate (noun)	physiology (noun)
	processes and functions of an organism
	the branch of the biological sciences dealing with the functioning of organisms

irritate (verb)	physiology (verb)
excite to an abnormal condition, or chafe or inflame
excite to some characteristic action or condition, such as motion, contraction, or nervous impulse, by the application of a stimulus
cause annoyance in; disturb, especially by minor irritations