yawn
A reflex of inhaling air and simultaneous stretching of the eardrums. The exact propose for yawning is unknown but often appears as a sign of fatigue or boredom/not impressed(emotion). It is also often paired with closed_eyes.
Yawning is very notable for being quite literally contagious.
Related:
The following tags are aliased to this tag: yawning (learn more).
This tag implicates open_mouth (learn more).