from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. So shocked or astonished as to be rendered speechless.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. so shocked as to be unable to speak
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. as if struck dumb with astonishment and surprise
From dumb + struck. (Wiktionary)