brother-out-law noun3 •The brother of one's boyfriend or girlfriend. •The boyfriend of one's sister or brother.Eust[ace]. My brother Out-lavv, and my ovvne true brother! / Cha[rles]. For euer thus let vs embrace each other. — 1592 •The brother of one's ex-spouse.Going home and hanging out with his daughter and brother-in-law, Ex-brother-in-law? Brother-out-law? seemed a whole lot better than whatever was going to happen inside that restaurant. — 2018 formsbrothers-out-law
