When she saw the surprise party, she was left speechless.
astonished
Frequency:
60
%
He was astonished by the magician's tricks.
stunned
Frequency:
50
%
The news of his promotion left him stunned.
bewildered
Frequency:
45
%
The complicated instructions left him bewildered.
flabbergasted
Frequency:
40
%
She was flabbergasted by the size of the mansion.
Idiomatic Expressions for dumbfounded
Phrase: dumbfounded by the sheer stupidity
Meaning: to be amazed or astonished by the extreme foolishness of something
Usage: He was dumbfounded by the sheer stupidity of their decision.