Definition of stupefying adjective from the Oxford Advanced Learner's Dictionary

stupefying

adjective
ˈstjuːpɪfaɪɪŋ
 
; ˈstuːpɪfaɪɪŋ
 
 
1 making you unable to think clearlystupefying boredom2 very surprising or shockingHis next action was utterly stupefying.stupefyingly
ˈstjuːpɪfaɪɪŋli
 
; ˈstuːpɪfaɪɪŋli
 
adverbThe party was stupefyingly dull.