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.

When you try to type :D but hit L instead of :

1. Long Dick (Jake from 'Booty Call' www.romp.com)
2. Lock Down
3. Low Down

v. Lickin' and Dickin'. Providing oral sex followed by vaginal and/or anal intercourse to a man's sexual conquest.

Lethal Dosage. L.D. is a pharmacological term used by the medical industry to standardize the toxicity of chemicals, specifically. In huge medical books, medical scientists and doctors have a standardisation for every single thing that you can possibly have in your body.