To stupefy means to shock someone so completely that they can barely think or react. When you're stupefied, you're so surprised or confused that your mind goes blank, like when you see a magic trick so incredible that all you can do is stand there with your mouth open.

Being stupefied isn't about lacking intelligence. It's about being temporarily overwhelmed. A sudden loud noise might stupefy you for a moment. Learning that your best friend is moving away might leave you stupefied. A plot twist in a book can stupefy readers who thought they had everything figured out.

Stupefying events or revelations stop you in your tracks. Imagine discovering that your quiet classmate is actually a champion chess player, or learning that the Earth travels around the sun at about 67,000 miles per hour. These facts might stupefy you because they're so unexpected or hard to grasp.

The related noun is stupefaction, which describes that dazed state of being unable to think clearly. When characters in stories stand in stupefaction, they're frozen by shock or disbelief, at least until their minds catch up with what just happened.