Entry 1 sense Webster, 1913 astounded · IPA /əstˈaʊndɪd/ 01 adj. struck with an intense and usually sudden surprise sufficient to produce wonder or perplexity 1. struck with an intense and usually sudden surprise sufficient to produce wonder or perplexity Syn. amazed, astonied, astonished, dumbfounded, flabbergasted, stunned, stupefied, thunderstruck