1. [adj]  knocked unconscious by a heavy blow
2. [adj]  in a state of mental numbness especially as resulting from shock; "he had a dazed expression on his face"; "lay semiconscious, stunned (or stupefied) by the blow"; "was stupid from fatigue"
3. [adj]  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"

STUNNED is a 7 letter word that starts with S.