1. The state of being a flattard.
2. An insult to one's intelligence.
The word flattarded originates from the derogatory name for people who believe the Earth is flat, or "flattards". Flattarded is used as an alternative to the popular insult "retarded" and is generally considered to be more derogatory in nature.
John: "I can't believe you think the Earth is a globe it's obviously flat!"
Bill: "Fucks sake John I didn't know you were this flattarded."
A flametardo is a double slander of someone who acts both 'Gay' (not in the sexual sense, but more like calling someone a Gaylord'" and Retard as the same time.
John Doe swears that 'The Holiday' is a great movie (He's begin 'Gay' or a 'Flamer') and that Jennifer Aniston is in the movie (He's retarded, because she's not). Therefore John is officially a Flametardo.