If you are astounded by something, you are very shocked or surprised that it could exist or happen. I was astounded by its beauty I am astounded at the comments made by the Chief Superintendent. = astonished. very surprised or shocked = astonished astounded by/at
filled with the emotional impact of overwhelming surprise or shock; "an amazed audience gave the magician a standing ovation"; "I stood enthralled, astonished by the vastness and majesty of the cathedral"; "astounded viewers wept at the pictures from the Oklahoma City bombing"; "stood in stunned silence"; "stunned scientists found not one but at least three viruses"
If something astounds you, you are very surprised by it. He used to astound his friends with feats of physical endurance. = astonish. to make someone very surprised or shocked = astonish (Probably from the past participle of astone; ASTONISH)