Definition
To secretly find something amusing or ridiculous, often without showing it.
竊笑
She pretended not to be interested in the joke, but I knew she must have been laughing up her sleeve.
她假裝對這個笑話不感興趣，但我知道她一定在暗自竊笑。
When the boss announced the absurd policy, the employees remained outwardly silent, but privately they were laughing up their sleeves.
當老闆宣布這荒謬的政策時，員工們表面上保持沉默，但私下都在暗自竊笑。
He tried to keep a straight face, but I saw the corners of his mouth twitch, knowing he was laughing up his sleeve.
他試圖保持嚴肅的表情，但我看到他嘴角抽動，知道他一定在暗自竊笑。