dumbfound

UK: dʌmˈfaʊnd | US: dʌmˈfaʊnd

Definition
  1. vt. to astonish or confuse someone to the point of speechlessness

  2. vt. to render someone temporarily unable to react due to shock or surprise

Structure
dumb <silent>found <strike>
Etymology

Coined in the 17th century as a portmanteau of dumb and confound (to confuse), blending the idea of being struck (found) into silence (dumb). The word vividly captures the physical reaction of shock—mouth open but no words uttered.

Examples
  1. The magician's trick dumbfounded the entire audience.

  2. She was dumbfounded by the sudden news of her promotion.

  3. His rudeness left me dumbfounded for a moment.

  4. The scientist's discovery dumbfounded skeptics.

  5. They stood dumbfounded as the fireworks lit up the sky.