stupefy

stu|pefy /stj'uːpɪfaɪ, st'uː-/ (stupefies stupefying stupefied)
[VERB] V n
If something stupefies you, it shocks or surprises you so much that you cannot think properly for a while. (FORMAL)
...a violent slap on the side of the head, which stunned and stupefied him.