a message whose content is at variance with reason
a ludicrous folly
"the crowd laughed at the absurdity of the clown's behavior"
That which is absurd; an absurd action; a logical contradiction.
The word "absurdity" entered English around 1472 via Middle French or directly from Late Latin, where it originally meant dissonance or incongruity. It is formed by combining the root for "absurd" with a suffix indicating a quality or state.