live in sin1 old-fashionedLIVE WITH somebody if people live in sin, they live together and have a sexual relationship without being married （未婚）同居；姘居 → live togetherlive in sin• We were, after all, living in sin, and she was a devoted Catholic.
→ live in sin at live1(8)
2 old-fashionedRELATIONSHIP if two people live in sin, they live together in a sexual relationship without being married 〔未婚男女〕同居，姘居live in sin• We were, after all, living in sin, and she was a devoted Catholic.
→ live in sin at sin1(2)