WordWeb Online

1. So surprisingly impressive as to stun or overwhelm
   "the figure inside the bouclé dress was stupefying"
   - astonishing, astounding, staggering
    
2. Making physically stupid or dull or insensible
   "a stupefying blow to the head"; "the stupefying effects of hemp"
    
3. Shocking with surprise and consternation
   "the stupefying impact of the tragedy"

1. Make dull or stupid or muddle with drunkenness or infatuation
   - besot
    
2. Be a mystery or bewildering to
   - perplex, vex, stick, get, puzzle, mystify, baffle, beat, pose, bewilder, flummox, nonplus, gravel, amaze, dumbfound
    
3. Make senseless or dizzy by or as if by a blow
   - stun

See also: alarming, disorienting, impressive, stupefaction

Type of: bedevil, befuddle, confound, confuse, desensitise [Brit], desensitize, discombobulate, fox, fuddle, immobilise [Brit], immobilize, throw