astound (v.)youdaoicibaDictYouDict
mid-15c., from Middle English astouned, astoned (c. 1300), past participle of astonen, astonien "to stun" (see astonish), with more of the original sense of Vulgar Latin *extonare. Related: Astounded; astounding.
stupendous (adj.)youdaoicibaDictYouDict
1660s, correction of earlier stupendious "causing astonishment, astounding" (1540s), from Late Latin stupendus "to be wondered at," gerundive of Latin stupere "be stunned, be struck senseless, be aghast, astounded, or amazed" (see stupid). Related: Stupendously; stupendousness.