Saying one thing while meaning another, often the opposite. The true meaning is left to the reader or listener.
In The Magic Mountain
Can one narrate time itself, time as such, in and of itself? No, indeed not, such a thing would be an insane audacity!
The narrator declares that narrating time "would be an insane audacity" and, shortly after, does exactly that. A denial stated with conviction and contradicted by practice is the irony of someone who knows his own book.
Chapter VII: Peeperkorn, the Great Boredom and the Thunder, the narrator