Attic salt

A shrewd, cutting, or subtle humor or wit. Also referred to as "Attic wit." Marianne was known to pepper her conversation with a bit of Attic salt, so she was quite popular at dinner parties. He lays on the Attic salt a bit too often for my taste; I can never tell when he's being serious. Ho ho, there's that Attic salt we know and love! That's why we asked you to host the evening.