What does musha mean in Russian?

"Musha" is not a word in Russian. It's possible you're thinking of a word from another language that sounds similar.

Could you please provide more context? For example:

* Where did you hear this word? (A book, a song, a movie, etc.)

* What was the word used for? (A name, a place, a thing, etc.)

This will help me understand what you're looking for and give you a better answer.