Bastardized pronunciation of "America" based on former President George W. Bush's Texan accent. Used to refer to anything sterotypically overly patriotic/rednecky american.
Can be used positively or derogatorially
As a positive-
Jane: "Why Do you like football so much?"
Joe: "Cuz' it's a real AMURIKAN sport, that's why!"
As a Negative-
Joe: "I have 15 pistols, 10 assault rifles, 5 rocket luanchers, and an M1A1 Abrahms Tank! The second ammendment ROCKS!
Jane: (sarcasm) "How very Amurikan of you..."