irritation vs irritate

irritation is a noun but irritate is not a noun.

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

irritation (noun)	irritate (noun)
unfriendly behavior that causes anger or resentment
the act of troubling or annoying someone
an uncomfortable feeling of mental painfulness or distress
a sudden outburst of anger
the psychological state of being irritated or annoyed
the neural or electrical arousal of an organ or muscle or gland
(pathology) abnormal sensitivity to stimulation

irritation (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