"irritate" in the verb sense

1. annoy, rag, get to, bother, get at, irritate, rile, nark, nettle, gravel, vex, chafe, devil

cause annoyance in disturb, especially by minor irritations

"Mosquitoes buzzing in my ear really bothers me"

"It irritates me that she never closes the door after she leaves"

2. irritate

excite to an abnormal condition, or chafe or inflame

"Aspirin irritates my stomach"

3. irritate

excite to some characteristic action or condition, such as motion, contraction, or nervous impulse, by the application of a stimulus

"irritate the glands of a leaf"

Source: WordNet® (An amazing lexical database of English)

Princeton University "About WordNet®."
WordNet®. Princeton University. 2010.

View WordNet® License