to open the mouth wide and inhale, usu in reaction to fatigue or boredom

to be menacingly wide, deep, and open; to gape

a yawning chasm

to utter (something) with a yawn

a deep usu involuntary intake of breath through the wide open mouth

informal a boring thing or person

She has even formed her own film and video group because she finds most training films ‘a yawn a minute’ — David Oates, Derek Ezra