This is the 8279th most frequent Russian word.
мб
"мб" is an informal abbreviation in Russian meaning "maybe" or "possibly."
Here, "мб" is used informally to mean "maybe," indicating an uncertain assumption about a future event.
Мб завтра будет хорошая погода, и мы сможем погулять.
Maybe tomorrow the weather will be nice, and we can take a walk.
In this sentence, "мб" functions as a shorthand for "может быть," signaling a non-committal likelihood.
Он сказал, мб он придет, но не обещает.
He said maybe he will come, but he does not promise.
Here, "мб" is applied casually in dialogue to propose a suggestion or possibility.