To twiddle one’s thumbs 意為「(等候的時候) 閒著沒事，閒著無聊」。Twiddle 這個字於 1540 年代開始用來指「無聊地或緊張地旋弄、把玩或擺弄 (拇指或手指)」，可當及物或不及物動詞用，如 John was twiddling (with) a pencil. (約翰在旋弄鉛筆)；The girl was twiddling (with) her hair. (那位女孩在把玩她的頭髮)。
To twiddle one’s thumbs 這個慣用語的字面意思為「無聊地旋弄兩手的大拇指」，於 1800 年代中期開始用作上述的比喻意思。
例句：
- Several students arrived early for the lecture on English grammar, so they were twiddling their thumbs for more than half an hour. (有幾個參加這項英文文法講座的學生來早了，他們百般無聊地等了超過半小時)
- Jimmy just sat there for three hours, twiddling his thumbs, while his boss made call after call. (在他的老闆一通接一通地打著電話時，吉米就在那裡閒著無聊地坐了三個鐘頭)