I have four sisters and here are their nicknames:
Grandma named Snootza because she was always snooping at Grandma's house.
Codfish got her name from Dad who caught her putting red salmon eggs in her mouth thinking they were candy.
And Big O and Little O were the two youngest girls named this by an uncle. He said every time he came over in the morning to visit they were always sitting at the table eating CheeriO's for breakfast.
And me, well, mine's about as bad as Codfish, maybe worse. I got the name "Skunk" from my Dad. Why? That's a dumb question! I got squirted by a skunk once, I guess, I don't remember. But I never asked why and he never told me why. So that's my answer and I'm sticking to it!