be suddenly unable to speak (because of shock, fear, etc.): We were struck dumb at the sight of three armed soldiers in the kitchen. ♢ The witnesses were struck dumb with terror. ▶ ˈdumbstruck adj.: When I found out that I had won first prize, I was dumbstruck.
President Clinton seemed to have been struck dumb. And strangest of all, the word "government"--denoting, literally, something every one of the world's hundreds of societies has--was so negatively valenced that it could no longer be uttered openly in American politics.