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c.1300, yenen, yonen, from Old English ginian, gionian "open the mouth wide, gape," from Proto-Germanic *gin- (cf. Old Norse gina "to yawn," Dutch geeuwen, Old High German ginen, German gähnen "to yawn"), from PIE *ghai- "to yawn, gape" (cf. Old Church Slavonic zijajo "to gape," Lithuanian zioju, Czech zivati "to yawn," Greek khainein, Latin hiare "to yawn, gape," Sanskrit vijihite "to gape, be ajar"). Related: Yawned; yawning.
"act of yawning," 1690s, from yawn (v.). Meaning "boring thing" is attested from 1889.
v. yawned, yawn·ing, yawns
To open the mouth wide with a deep inhalation, usually involuntarily from drowsiness, fatigue, or boredom. n.
The act of yawning.