Apophasis: Saying something by denying that you’ll say it; the “I’m-not-saying-I’m-just saying” rhetorical device. From the Greek roots apo- (away from, off) and -phatikos (to speak): “to deny.” Entered English in a 1656 rhetoric text, when it was defined as “a kind of irony.” Pronounced (ə-pŏf′ə-sĭs). Apophasis is also known as praeteritio (“passing over”).
Apophasis has been used by orators from Cicero on. It’s a favorite device of one of the candidates in the U.S. presidential race, and also by whoever handles his Twitter account.
I refuse to call Megyn Kelly a bimbo, because that would not be politically correct. Instead I will only call her a lightweight reporter!— Donald J. Trump (@realDonaldTrump) January 27, 2016
From a rally last week in Iowa:
“I was gonna say that De Blasio’s the worst mayor in the history of our city but I couldn't say it, oh he's a terrible mayor .. but I was gonna say that but now I won’t say that.”
And on Saturday, in response to the accusation during the Democratic National Convention from bereaved Army father Khizr Khan that Trump had “sacrificed nothing”:
"If you look at his wife, she was standing there. She had nothing to say. She probably, maybe she wasn't allowed to have anything to say. You tell me."
(Mrs. Khan said in interviews with MSNBC and ABC that she didn’t speak because she was “in pain.”)
At the end of his second term, President Ronald Reagan used apophasis in a dig at Democratic candidate Michael Dukakis, who was rumored to have suffered from depression: “Look, I’m not going to pick on an invalid.” Reagan later said he was “just trying to be funny.”
For an alphabetical list of rhetorical devices, see Phrontistery.
And for more on the uses of rhetoric, see Argue Lab.