Common meanings I can think of off the top of my head... 1. Exasperation. もう！「やめて」といったんでしょう！ "Jeez! Didn't I already tell you to stop!" 2. Already. もう終わりました。 "It already ended." 3. Anymore. 「もう諦めない、絶対に。」 "I won't give up anymore, no matter what."

もう has several translations depending on the situation, context, etc, so we can't describe the meaning only with the wordもう. Chip answered very well, and I don't know about what you want to know.