Phrasal Verb: joint Posted on 8th May 201627th March 2016 by DoubleClick joint in means take part in an activity that is already going on. (e.g. We’re playing a game. Why don’t you join in?) More Phrasal Verbs… Share this:Click to share on Twitter (Opens in new window)Click to share on Facebook (Opens in new window) Related Posted in Phrasal Verb and tagged joint, Phrasal verb.