vt.

1. 使惱怒；使煩躁
   His letter irritated me a little.

   他的信使我有點惱火。

2. 使過敏；使難受；使發炎；使疼痛
   These tight shoes irritate my toes.

   我的鞋太緊，夾痛我的腳趾。

3. 刺激，使興奮

vi.

1. 引起惱怒；引起不愉快

v.

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.