cunt-act
An act that is not only cunt-like, but somehow, ineffably goes against all the principles of mateship that we currently abide by.  It implies a selfish inconsideration of others, and perhaps....  yes, an active ill-will in some cases.  When uttered, "cunt-act" (or "cunts-act") is often accompanied by a mournful shake of the head.
Yo, trAse, taking the last beer was a fucking cunt-act and you know it :grr: