What is whiskey in a teacup meaning?

"Whiskey in a teacup" is an American idiom that means appearing to be delicate or refined on the outside, but having a tough, strong personality on the inside. The metaphor refers to the idea of serving hard liquor, like whiskey, in a delicate teacup - a contrast between the strong flavor of the drink and the delicate vessel it's served in. The phrase has become popularized in recent years as the title of a bestselling memoir by American actress, producer, and author, Reese Witherspoon.