Open-mouthed

Full definition of open-mouthed

Adjective

1. (obsolete) Talkative, speaking freely.
• 1485, Thomas Malory, Le Morte Darthur, Book XVIII:many in the courte spake of hit – and in especiall Sir Aggravayne, Sir Gawaynes brothir, for he was ever opynne-mowthed.
2. With the mouth open.
3. Gaping in surprise, wonder or astonishment.