1. When two people get together and start a romantic or sexual relationship. (We usually use this to talk about other people's behaviour, not our own). E.g. "I'm in my 30s now and all my friends seem to be pairing off and getting married, but I'm still single" -to pair off 2. -to pair someone off with someone = to try and make two people start having a romantic or sexual relationship together. "I think your wife is trying to pair me off with her friend". More info at http://teacherluke.co.uk/phrasal-verb-a-day/112-to-pair-off/