A ?? RE: the meaning of pilot's nicknames...

[NickM]

Guys:

Some of the better known JW aces had nicknames...some I know:
Erich Hartmann was called 'Bubi'(boy or kiddo) because of his youth, Robert Weiss was called 'Bazi' (which someone translated as 'Rascal') but I have a couple more that I have questions about:

Wilhelm-Ferdinand 'Wutz' Galland;
Emil 'Bully' Lang;

So guys, what do these nicknames mean, if you were to translate them, approximately?

thanks, ahead of time

NickM