The English word "quit" exists in the German, language too, as "quitt".
With some slightly different meanings.
Basically, it's almost the same as "quit" : Ending of something.
The German "quit" however, is almost (as far as I know) only used in the saying "ich bin mit dir quitt !" or "ich bin quitt mit dir !"
This also means "ending of something : In this case the ending of an relationship.
This saying is not meant to be friendly; it's rather the expression of somone who has "had enough" of somebody else, no matzter what the reasons might be. It expresses the will of someone to instantly end or stop an relationship - for example because he or she is angry or doesn't trust the other one anymore.
To use the word "quitt" in other sentences like this saying sounds some kind of antiquated, but is still possible. People will understand it.
(Please note that I'm not speaking of dialects here ... actually I'm even not sure whether the use of this word is only common in dialects or not ...)
"Quitt" in German means an instantly ending of something. You should rather prefer the word "stop", because it's kind of wider known as "quitt".
The "Quitte" is a fruit of the Quittenbaum (Quitten-Tree). It has become quite rare and I think it has wandered upon the "Red List" of plants and animals that have become rare in nature. It has become a seldom sight in our nature. Nevertheless there exists some kind of liqueur of it. THe fruit itself looks a bit like a small, yellow apple, but without the apple's peel and much softer.
