Balderdash means nonsense or foolish talk that makes no sense at all. When someone says something completely ridiculous or obviously untrue, you might think, “What balderdash!”

The word has a wonderfully dismissive sound to it, as if you're sweeping away silly ideas with one dramatic word. If your friend claims they can fly by flapping their arms hard enough, that's balderdash. If someone insists that two plus two equals five, you're hearing pure balderdash.

Balderdash is stronger than just being wrong. It suggests that what's being said is so absurd it's almost amusing. A scientist might politely say a theory is “incorrect,” but if someone claims the moon is made of green cheese, that's balderdash.

The word often appears when people want to sound both emphatic and a bit playful about calling out nonsense. “Balderdash!” works as a complete exclamation on its own. There's also a popular board game called Balderdash, where players make up ridiculous fake definitions for real words, trying to fool each other with creative nonsense.