Meanings
A bigoted and ultraconservative person

Examples
I'm sorry, but I can't agree on such kind of redneck thinking
Mi dispiace, ma non riesco a condividere questo tuo modo di pensare tanto ultraconservatore

Origin
This term, originating as an allusion to a farmer's perennially sunburned neck, usually refers to the poor white farmers of the southern U.S., who are notorious (at least most of them) for their intolerance and racism. Nowadays, the word is used of any such person, in or out the South