Synonyms of flabbergast in English:

flabbergast


See US English definition of flabbergast

See UK English definition of flabbergast

verb

1‘we were flabbergasted when we found out’

SYNONYMS
astonish, astound, amaze, surprise, startle, shock, take aback, take by surprise
dumbfound, strike dumb, render speechless, stun, stagger, stop someone in their tracks, take someone's breath away, confound, daze, overcome, overwhelm, nonplus, stupefy, disconcert, unsettle, bewilder
informal bowl over, knock for six, knock sideways, knock the stuffing out of, floor
British informal gobsmack