swear: [OE] Swear is a general Germanic word, with relatives in German schwören, Dutch zweren, Swedish svärja, and Danish sverge. They all go back to a prehistoric Germanic *swarjan, a derivative of the base *swar-, which also lies behind the second syllable of English answer. And this in turn may come ultimately from the same Indo-European base as produced English sermon. The verb’s original meaning was ‘take an oath’; its use for ‘curse, blaspheme’ dates from the 15th century. => answer[swear etymology, swear origin, 英语词源]