A cunning mixture between Bastard and Twat, used when someone is bad enough to be both at the same time. Also as it is not technically a swear word, no one should have any objections with you shouting at them!
The word: " Twastard" is a noun and an amalgam of the words: "Twat" and "Bastard." Basically calling a person both insults at once making it a serious swear word and a double revilement. Generally used against males rather than females
"You little twastard, how dare you steal my money." Or, "Look at the right twastard Johnny has turned into."