Also used to describe a chic restaurant or bar frequented by "beautiful people" (esp. media/fashion/art types), when it is often shortened to a single "mwah"
An evil laugh. A laugh one does when they are about to do something evil. Such as when a villan has a plot to take over the world, he does this laugh right before it goes into effect. Also a noise made by people who have just gotten away with an evil deed or crime.