Used to express dislike, hate, lack of understanding, loathing or general antipathy towards someone or something.

Adding vowels into the equation adds vehemence to one's assertion, as does expletives.

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.