live in sin
未婚同居，指未结婚的情侣一起生活
口语·略带幽默或传统语境
英文释义
to live together as a couple without being married
例句
They decided to live in sin for a few years before getting married.
典故来源
源自基督教传统，将未婚同居视为违背教义的“罪恶”，20世纪后逐渐中性化。