dumbfounded

American  

[duhm-foun-did, duhm-foun-] / dʌmˈfaʊn dɪd, ˈdʌmˌfaʊn- /

Or dumfounded

adjective

1. speechless with amazement; astonished or showing astonishment.

   I smiled at the dumbfounded look on their faces as their eyes widened and their mouths fell slack.

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verb

1. the simple past tense and past participle of dumbfound.

Etymology

Origin of dumbfounded

dumbfound ( def. ) + -ed ² ( def. )

Example Sentences

"So it's pretty ludicrous... I'm dumbfounded in terms of the stark contrast that exists currently in the landscape of sport and swimming."

From BBC

And though some of the names listed have since been implicated in his crimes, or at least knew about his conviction, many others were dumbfounded to be mentioned at all because they’d never met Epstein.

From The Wall Street Journal

Ordinary air travelers have been dumbfounded by the chaos.

From The Wall Street Journal

I was so dumbfounded I couldn’t even think straight, much less say anything.

From Literature

American skater Nathan Chen, the Beijing men's individual gold medallist, was dumbfounded, saying: "What a shock".

From Barron's