We openly refer to my ex -- the abuser discussed in my last post -- as "The Jackass".
I can't remember precisely how it came about, but I'm probably not far off in saying that The Jackass had done something jerk-tastic in front of my parents. Because, yes, he really was that big of a douchebag.
Dad referred to him as a "jackass", and it stuck. (And let me tell you, he lived up to -- or perhaps down to -- the name!)