Several steps beyond a regular bastard, someone so treacherous, conniving, and evil that you can't believe how much of a bastard they really are. Typically uttered after the unbelievable bastard has done something shockingly wicked.
After seeing millions of bodies littered across the landscape, all I could do was turn to the man responsible and say, "you unbelievable bastard..."
by RySenkari July 29, 2009
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