Concubinage
/ˈkɒn.kjʊ.bɪ.nɪdʒ/
Synonyms
- cohabitation
- extramarital relationship
- mistressship
- paramourship
Slang Meanings
Shacking up
They've been shacking up for years without tying the knot.
Live-in partner
He considers her his live-in partner, but they aren't officially married.