Recently, I published a post here arguing that German has no word for "bully" because there is no such thing over here. Now, Michael Quinion has published an interesting comment on the etymology of this word. It turns out that German does indeed have the same word, at least etymologically.
"Bully" goes back, he says, to the Dutch boel, which immediately took me to the German Buhl, a word that today only appears in the term Nebenbuhler, perhaps best translated as a rival for a lover's attention. The Dutch word (and the antiquated German Buhl, no longer in common use) both basically mean "lover."
So it turns out that our bully was once a lover. I guess that only goes to show that love and hate are as close as they say. Anyway, if you want the real etymology, visit Michael's website.