yawn
v.v. to open your mouth wide and take a deep breath because you are tired or bored. It is something your body does automatically.
v. to involuntarily open the mouth wide and inhale deeply, typically as a physiological response to fatigue, boredom, or drowsiness.
I always yawn when I stay up too late.
The students began to yawn as the lecture stretched into its third hour without a break.
Observing someone else yawn often triggers a reciprocal response in the viewer, a phenomenon known as contagious yawning that is linked to social bonding and empathy.
Partly from Middle English yanen, yonen, yenen (“to yawn”), from Old English ġeonian, ġinian (“to yawn, gape”), from Proto-West Germanic ginōn, from Proto-Germanic ginōną (“to yawn”); and partly from Middle English gonen (“to gape, yawn”), from Old English gānian (“to yawn, gape”), from Proto-West Germanic gainōn, from Proto-Germanic gainōną (“to yawn, gape”); both from Proto-Indo-European ǵʰi-, ǵʰeyh₁- (“to yawn, gape”). Cognate with North Frisian jåne (“to yawn”), Saterland Frisian jaanje, joanje (“to yawn”), Middle Dutch genen, ghenen (“to yawn”), German Low German jahnen (“to yawn”), German gähnen (“to yawn, gape”), dialectal Swedish gana (“to gape, gawk”), dialectal Norwegian gina (“to gape”). Compare also Old Church Slavonic зѣѭ (zějǫ) (Russian зи́нуть (zínutʹ), зия́ть (zijátʹ)), Greek χαίνω (khaínō)), Latin hiō, Tocharian A śew, Tocharian B kāyā, Lithuanian žioti, Sanskrit जेह् (jeh)
The verb is intransitive and does not take a direct object.