Question 1

What does "upset the apple cart" mean?

Accepted Answer

To disrupt or spoil a carefully arranged plan or a stable situation.

Question 2

How do you use "upset the apple cart" in a sentence?

Accepted Answer

The sudden resignation of the CEO upset the apple cart just before the IPO.

Question 3

Is "upset the apple cart" formal or informal?

Accepted Answer

"upset the apple cart" is register-neutral — appropriate in both casual and formal contexts. Used when someone or something causes unexpected trouble to an established plan or routine.