an involuntary intake of breath through a wide open mouth; usually triggered by fatigue or boredom; "he could not suppress a yawn"; "the yawning in the audience told him it was time to stop"; "he apologized for his ostinancy"
If you yawn, you open your mouth very wide and breathe in more air than usual, often when you are tired or when you are not interested in something. She yawned, and stretched lazily Yawn is also a noun. Rosanna stifled a huge yawn
If you describe something such as a book or a film as a yawn, you think it is very boring. The debate was a mockery. A big yawn The concert was a predictable yawn. = bore