prison 監獄
in prison 在坐牢
She is in prison. 她在坐牢。
He's spent a lot of time in prison.
他坐了很久的牢。

be sent to prison 被關押
She was sent to prison for six months.
她被關了六個月。

go to prison 進監獄
She went to prison for six months.
她被關了6個月。

prisoner 犯人，囚犯
take no prisoners (為達目的）不擇手段，不顧他人感受。
When he gets angry, he takes no prisoners.
他一生氣，就完全不顧他人的感受。

culprit 罪犯；肇事者(someone who has done something wrong, or, a fact or situation that is the reason for something bad happening)
People are getting much fatter, and milk tea is one of the main culprits.
現在人都越來越胖了，奶茶就是元兇之一。

wrongdoer 做壞事的人，違法犯罪的人（a person who does something dishonest or illegal）
He is a wrongdoer because he cheated on his girlfriend.
他做錯了事情，因為他劈腿了。