flabbergasted

US /ˈflæb.ɚ.ɡæs.tɪd/
UK /ˈflæb.ɚ.ɡæs.tɪd/
1.

sửng sốt

feeling shocked, usually because of something you were not expecting:

:
•
When they announced her name, the winner just sat there, flabbergasted.