A particular situation in life that is detrimental to one's cause.
Matt-" My front tire blew and I rolled my car 11 times @120k/hr in a school zone"
Stu-"What a fuckin' 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: