I've gotta quote tsuwm. I checked out asteism since that was news to me. It warn't in MW unabridged, so I checked onelook, and there tsuwm was along with 7 other references out of the over 800 availables.

And here's what tsuwm wrote about asteism:

asteism
[rhet] genteel irony, polite and ingenious mockery;
a... handsome way of deriding another -- Chambers