Not my dictionary. From Webster's: "a false statement made with deliberate intent to deceive."
1. a false statement made with deliberate intent to deceive; an intentional untruth; a falsehood.
2. something intended or serving to convey a false impression; imposture: His flashy car was a lie that deceived no one.
3. an inaccurate or false statement.4. the charge or accusation of lying: He flung the lie back at his accusers.
–verb (used without object)
5. to speak falsely or utter untruth knowingly, as with intent to deceive.
6. to express what is false; convey a false impression.
–verb (used with object)
7. to bring about or affect by lying (often used reflexively): to lie oneself out of a difficulty; accustomed to lying his way out of difficulties.
—Idioms
8. give the lie to,
a. to accuse of lying; contradict.
b. to prove or imply the falsity of; belie: His poor work gives the lie to his claims of experience.
9. lie in one's throat or teeth, to lie grossly or maliciously: If she told you exactly the opposite of what she told me, she must be lying in her teeth. Also, lie through one's teeth.
Random House Unabridged Dictionary.
At least you're not denying he's a retard.