Live In Sin Meaning
(intransitive, idiomatic) To cohabit as if man and wife without being married.
Example: 1922, John Galsworthy, A Family Man, act 2:
Ralph: Athene gone and got married?
Builder: No. It'sâ€”it's that she's gone andâ€”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.