punctual (adj.)youdaoicibaDictYouDict[punctual 词源字典]
c. 1400, from Medieval Latin punctualis, from Latin punctus "a pricking" (see point (n.)). Originally "having a sharp point; of the nature of a point;" meaning "prompt" first recorded 1670s, from notion of "insisting on fine points." Related: Punctually.[punctual etymology, punctual origin, 英语词源]