physiology vs irritate

physiology is a noun but irritate is not a noun.

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

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

physiology (verb)	irritate (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