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)
To astonish; to strike with amazement; to confound with wonder, surprise, or fear
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 is astounding, you are shocked or amazed that it could exist or happen. The results are quite astounding. = amazing, astonishing + astoundingly astound·ing·ly astoundingly blue eyes. so surprising that it is almost impossible to believe = astonishing
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"