openmouthed

/OW1 P AH0 N M AW1 DH D/
adjective
  1. 1

    Talkative, speaking freely.

  2. 2

    With the mouth open.

  3. 3

    Gaping in surprise, wonder or astonishment.

Synonyms

Source: https://en.wiktionary.org/wiki/open-mouthed, https://en.wiktionary.org/wiki/openmouthed