- brother-in-law (n.)
[brother-in-law 词源字典]
- c. 1300; also brother in law; see brother. In Arabic, Urdu, Swahili, etc., brother-in-law, when addressed to a male who is not a brother-in-law, is an extreme insult, with implications of "I slept with your sister."[brother-in-law etymology, brother-in-law origin, 英语词源]