もう
The definition of the particle varies depending on whether the verb is positive or negative.
If the verb is positive, the definition of もう is “already” :
Usage examples:
もう春です。
Mou haru desu.
It’s already spring.
もう食べました。
Mou tabemashita.
I’ve already eaten.
If the verb is negative, the definition of もう / mou is “not any more”:
私はもう、タバコを吸いません。
Watashi wa mou, tabako o suimasen.
I don’t smoke anymore.