yawning

showing lack of attention or boredom

“the yawning congregation”

an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom

“the yawning in the audience told him it was time to stop”

gaping open as if threatening to engulf someone or something

“the yawning mine shaft”

with the mouth wide open indicating boredom or sleepiness

“a yawning congregation”