to tell you the truth, I had never heard it before until about a month ago
my first reaction was that it was an abbreviated form of something like savant...not quite
then *and this will both offend you and get you a definition for any slang word that you could ever possible hear* I decided to try urbandictionary.com
ignoring the obscenities, it's actually taken from savage...which, from "current" definitions would mean someone who is really cool, "hardcore," awesome, or great at whatever they do
thus, it
is a compliment