Is it rude to yawn in a very boring formal meeting?

So imagine yourself in a meeting/convention/discussion/or any other formal gatherings and the situation is so unexpectedly boring. Whether the speaker say pointless things or something that you’ve already known about all of it or else for a very long time till you feel so bored and are repeatedly tempted to yawn. Will you yawn? Do you think it’s offensive to yawn in such situation?