as if struck dumb with astonishment and surprise; "a circle of policement stood dumbfounded by her denial of having seen the accident"; "the flabbergasted aldermen were speechless"; "was thunderstruck by the news of his promotion"驚きと驚愕で口がきけなくなるかのような吃驚仰天
例:The flabbergasted aldermen were speechless. 面くらった市会議員は口もきけなかった。