gobsmacked

 
Pronunciation: /ˈgɒbsmakt/

adjective

British informal
  • utterly astonished; astounded: the locals were gobsmacked when us lot trooped in

Derivatives

gobsmacking

adjective

Origin:

1980s: from gob3 + smack1, with reference to being shocked by a blow to the mouth, or to clapping a hand to one's mouth in astonishment