What is Says You?
1.
A declaration of denial. Deterring the accusations of others.
Bob: Hey Joe! You're a fag!
Joe: "Says you"
2.
An expression of disbelief, usually uttered after a sarcastic snort and always with a tone of derision.
"I licked Britney Spear's kneecap last night!"
"<snort>, yeah - says you!"
