open-mouthed (comparative more open-mouthed, superlative most open-mouthed)
- (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.
- With the mouth open.
- Gaping in surprise, wonder or astonishment.