Surprised describes how you feel when something happens that you did not expect. Your face and body often react quickly, with wide eyes or a sudden jump.
From the past participle of 'surprise', which came from Old French 'surprendre' meaning 'to overtake, seize unexpectedly'. The feeling word grew out of the idea of being suddenly 'seized' by an event.
The surprised facial expression—raised eyebrows, open mouth—is so universal that even babies and people from very different cultures show it. Your face is basically announcing, “My prediction just failed!” to everyone around you.
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