irritate

Concise Oxford English Dictionary © 2008 Oxford University Press:
irritate/ˈɪrɪteɪt/

▶verb

• 1 make annoyed or angry.

• 2 cause inflammation in (a part of the body).

• 3 Biology stimulate (an organism, cell, etc.) to produce an active response.

– derivatives
irritated adjective,
irritatedly adverb,
irritating adjective,
irritatingly adverb,
irritation noun,
irritative adjective,
irritator noun.

– origin C16 (earlier (ME) as irritation), in sense ‘excite, provoke’: from L. irritat-, irritare ‘irritate’.