(an-TIF-ruh-sis)
noun
The humorous or ironic use of a word or a phrase in a sense opposite of its usual meaning. For example: "Brutus is an honorable man." -Antony in Julius Caesar (Shakespeare)
Etymology
From Late Latin, from Greek antiphrazein (to express by the opposite), from anti- + phrazein (to speak)
Usage
"He was murmuring something between lips decorated by a little mustache, which gave a sarcastic touch to his clerk-like expression, a mustache folded over his mouth like an antiphrasis, which tinged whatever he said with maliciousness, no matter how solemn it was." — Edoardo Albinati & John Satriano; Story Written on a Motorcycle; Antioch Review (Yellow Springs, Ohio); Summer 1992.
"Perhaps Charles McGrath, in The New Yorker, sums up the ambivalence most eloquently. 'How good are these books really?' he asks, and answers: not so good--although he does so in the more flattering antiphrasis of 'good enough that you wish they were even better.'" — Neil Gordon; The Admiral; Village Voice (New York); Jun 6, 1995.