what's the big idea

phrase

informal

—used to ask why someone is doing or saying something

Hey! What's the big idea!?

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“What's the big idea.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/what%27s%20the%20big%20idea. Accessed 13 Mar. 2026.

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what's the big idea

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