This is the 949th most frequent Czech word.
můžu
"Can" or "I can."
Here, 'můžu' denotes the ability or permission of the speaker to offer help.
Můžu ti pomoct s úkolem?
Can I help you with your homework?
In this case, 'můžu' expresses a polite request for permission to go outside.
Můžu jít teď ven, prosím?
Can I go outside now, please?
Here, 'nemůžu', the negative form of 'můžu', conveys the impossibility or lack of ability to come tomorrow.