The one-word form of the phrase "Son of a bitch", commonly used by rednecks. Also spelled "Sonnuvabitch", "Sunnovabitch" and "Sonnovabitch", all present the same insult. Although mainly used by rednecks, it can be used by anyone, but it would sound weird.
"Hey Tom, that sunnuvabitch just tried to steal gas!"
"Get out, you sunnuvabitch!"
"I HOPE YOU DIE YOU SUNNUVABITCH!"
"Oh, Sunnuvabitch! I forgot to go to work!"