scruple: [16] Latin scrūpus meant ‘sharp stone’, and the notion of something troubling the mind like a painful stone in the shoe led to its metaphorical use for ‘anxiety, doubt, particularly over a moral issue’. Both meanings were carried over into the diminutive form scrūpulus, which also came to be used for a very small unit of weight. This passed into English via French scrupule as scruple, on the way losing the literal sense ‘small stone’. [scruple etymology, scruple origin, 英语词源]