Group Adding Cunt - One of those ballbags that you see on Facebook that joins literally every single group that's possible, even if it doesn't link to them in anyway; they still join the groups. Each day a G.A.C. will fill up your homepage with groups that relate to nothing.
1. This is probably what a G.A.C. says to them self on a regular basis, "I'm a wanker, let's join every group."
2. That G.A.C. on my homepage is joining all the groups today...again.