The facial orafice into which one shoves pie and other food items (ie: the mouth).

A stupid person; it refers to the lack of surface area on an individual's brain. The general thought is that the more surface area (wrinkles, creases, etc.) a brain has, the smarter the person is. Conversely, a person with a smooth brain (no wrinkles) has less surface area and would therefore be stupid.

The human mouth.

Noun. Mouth, i.e., the hole you ought to be using for eating (pie). From the British slang, cake-hole.

The mouth: because its a big hole into which you are able to shove pies.

The stinkin' mouth of an idiot who would not shut up
The face or trap of a noisy asshole
The mouth of B. Smith

the hole in your face that farts out annoying sounds all day while you are at work.