Bäh, interj.

An exclamation expressive of disgust or contempt; pah.

“Twenty-five years ago the vile ejaculation, Bäh! was utterly unknown to the English public. Now, and entirely through the currency given to it by our own novels, it has become the most popular expression for dismissing with contempt any opinion or suggestion of the person with whom you are conversing. Any thing more brutal or more insolent, in the way of summary contempt, can not be imagined.” De Quincey.