noun blending and clipping
originally from son-of-a-bitch; it has the same basic meaning but is used by a different group of people. "Sombitch" is still an insult, applied to men, meaning just a generally bad or disagreeable person. However, the neologism is allegedly used more by "rednecks", a stereotype for rural, Southern farm workers. In this case "som" is a clipping of "son-of-a", and then blended with "bitch" to make one word. I think this is also an approximation of how the original term sounds when said with a Southern accent.
That sombitch broke my tractor and stole my woman!
Etymology : from "son-of-a-bitch"; insult that has been in the English language since about 1700.
Source : friend at Rice University, October 2010
Last modified: 7 December 2010