flabbergasted
/ˈflæbəɡæstəd/verb
To astonish someone so completely that they hardly know how to react.
Example sentences
- “The surprise party flabbergasted him; he stood speechless at the door.”
- “We were flabbergasted by the size of the bill.”
You will almost always meet this as the adjective: 'I was flabbergasted.' Informal and deliberately theatrical; 'astonished' is the neutral choice.