adjective, verb, noun · misery, pain, or difficult circumstances in life

他从小吃了不少苦。

adjective, noun · having a sharp, pungent taste like that of unsweetened cocoa or quinine

这种药味道很苦。

adjective · with great effort, diligence, or intensive persistence

他苦钻研了五年，终于取得了突破。

verb · to bring hardship, misery, or distress to someone

这场大雨可苦了那些没带伞的人。

adjective · to undergo or experience physical or mental pain or distress

他一直为病痛所苦。