Meaning : Bewildering or striking dumb with wonder.
Synonyms : dumbfounding, dumfounding
Meaning : So surprisingly impressive as to stun or overwhelm.
Example :
Such an enormous response was astonishing.
An astounding achievement.
The amount of money required was staggering.
Suffered a staggering defeat.
The figure inside the boucle dress was stupefying.
Synonyms : astonishing, staggering, stupefying