say it: uh-STOWN-ding
astounding is an adjective meaning "bewildering or striking dumb with wonder". It carries 2 recorded senses.
bewildering or striking dumb with wonder
so surprisingly impressive as to stun or overwhelm
“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”
Definitions, synonyms and semantic relations for astounding come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.