flabbergast
/icons/point.icon SURPRISE, ASTONISH, ASTOUND, AMAZE, FLABBERGAST mean to impress forcibly through unexpectedness.
SURPRISE stresses causing an effect through being unexpected but not necessarily unusual or novel.
e.g. surprised to find them at home
ASTONISH implies surprising so greatly as to seem incredible.
e.g. a discovery that astonished the world
ASTOUND stresses the shock of astonishment.
e.g. too astounded to respond
AMAZE suggests an effect of bewilderment.
e.g. amazed by the immense size of the place
FLABBERGAST may suggest thorough astonishment and bewilderment or dismay.
e.g. flabbergasted by his angry refusal
https://gyazo.com/41d0d092645b86eaa7efcc240cc9df9a
source: [SHIROBAKOの宮森あおいが電話で仰天するGIF画像｜無料GIF画像検索 GIFMAGAZINE 699647]
verb with object (usually as adjective flabbergasted) informal
surprise (someone) greatly; astonish:
｟くだけて｠ ; 〖通例be ～ed〗 «…に» びっくり仰天する «at, by» .
e.g. this news has left me totally flabbergasted.
ORIGIN
late 18th century: of unknown origin.