gobsmacked [1930s] The word gobsmacked presumably refers either to the shock of being hit in the mouth or to the action of clapping your hand to your mouth in astonishment. Gob, an informal word for ‘mouth’ [M16th], probably comes from Irish and Scottish Gaelic gob ‘beak or mouth’. Gab, as in the gift of the gab and the adjective gabby, both early 18th century, are variants of gob. There is another gob [LME], ‘a lump of something’, that came into English from Old French gobe ‘mouthful or lump’ which may also be Celtic: gobble [E16th] is probably based on this gob.