To move quickly, leave a scene, to depart, to move on, to go.
Generally used an expression of leaving together in a group after waiting too long for people to make up their minds.
Nick: "Hey lads, we've been talking about this for ages - let's munt!"
Damo: "Indeed, let us munt!"
Matt: "before we munt, have you guys seen mu snakeskin watch?"
Phil: "Too many times Matthew, too many times..."