oscitance

(noun) drowsiness and dullness manifested by yawning. Synonyms: oscitancy.

(noun) an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom. Synonyms: yawn, yawning, oscitancy. Examples: "He could not suppress a yawn." "The yawning in the audience told him it was time to stop." "He apologized for his oscitancy."