gaping

Short definition from Wiktionary

Verb

1. 1
   present participle and gerund of gape

Adjective

1. 1
   Wide open.
2. 2
   Having the jaw wide open, as in astonishment or stupefaction.

Noun

1. 1
   The act of one who gapes.
2. 2
   Something gaping; something agape.
3. 3
   A threat or courtship behavior in animals involving holding the mouth open and displaying the teeth or other interior features.