neap (adj.)youdaoicibaDictYouDict[neap 词源字典]
Middle English, from Old English nepflod "neap flood," the tide occurring at the end of the first and third quarters of the lunar month, in which high waters are at their lowest, of unknown origin, with no known cognates (Danish niptid probably is from English). Original sense perhaps is "without power." As a noun from 1580s.[neap etymology, neap origin, 英语词源]