So shocked or astonished as to be rendered speechless.(adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "dumbstruck" in a sentence
"Midpoint between dismissive and dumbstruck is the objective mindset to appreciate how pragmatic idealism shaped Federico's leadership and patronage."
"Furthermore, the author says that the word dumbstruck in the expression "I was dumbstruck by the news" is a compound noun."
"And what teacher's notes in what context could have led one examinee to coin a word dumbstruck, which another candidate heard as "bumstruck"?"