live in sin

Verb

live in sin (third-person singular simple present lives in sin, present participle living in sin, simple past and past participle lived in sin)

1. (idiomatic, intransitive) To cohabit as if husband and wife without being married.
   • Ralph: Athene gone and got married?
     Builder: No. It's—it's that she's gone and—and not got married. . . . I suppose you'd have me eat humble pie and tell Athene she can go on living in sin and offending society.1922, John Galsworthy, A Family Man, act 2

   Synonyms:

   live over the brush, play house