Other forms: vapidities
Vapidity is a quality of being dull and uninspiring. The vapidity of your brother's favorite TV show makes you want to scream, but he can't get enough of it. There's no accounting for taste!
When the noun vapidity was first used in the 18th century, it mainly described flat, tasteless drinks: "The vapidity of this root beer makes it undrinkable." The Latin root, vapidus, means "flat or insipid," or literally "that which has exhaled its vapor," and is related to vappa, "stale wine." Today we're more likely to talk about a boring airhead's vapidity or complain about the vapidity of a dull new movie.