A blending of the two words inbred and redneck.
1.) A redneck considered so inept as to cause others to believe he is mentally challenged or inbred.
2.) An insult in a verbal pissing contest to those who are considered or conider themselves to be redneck. Like words are hick, hillbilly, etc.
1.) Person 1: Did you hear about (cletus)?
Person 2: No, I did not. What happened?
Person 1: He went deer hunting last weekend and the deer strapped HIM to the car.
2.) Inbredneck: If you don't like the way I drive, stay the hell off the highway. I pay taxes, so I can drive wherever I want, however I want.
Person 1: You were in the fast lane doing 40 next to an old man going the same speed and blocking traffic you damn inbredneck! If you'll notice, you'll see the signs that say "Slower traffic keep right."