Litotes, derived from a Greek word meaning “simple”, is a figure of speech which employs an understatement by using double negatives or, in other words, positive statement is expressed by negating its opposite expressions.
For example, using the expression “not too bad” for “very good” is an understatement as well as a double negative statement that confirms a positive idea by negating the opposite. Similarly, saying “She is not a beauty queen,” means “She is ugly” or saying “I am not as young as I used to be” in order to avoid saying “I am old”. Litotes, therefore, is an intentional use of understatement that renders an ironical effect.
From ‘Last Night in Sweden’? Trump’s Remark Baffles a Nation
, The New York Times, 19 February 2017, emphasis added:
Swedes reacted with confusion, anger and ridicule on Sunday to a vague remark by President Trump that suggested that something terrible had occurred in their country.
During a campaign-style rally on Saturday in Florida, Mr. Trump issued a sharp if discursive attack on refugee policies in Europe, ticking off a list of places that have been hit by terrorists.
“You look at what’s happening,” he told his supporters. “We’ve got to keep our country safe. You look at what’s happening in Germany, you look at what’s happening last night in Sweden. Sweden, who would believe this?”
Not the Swedes.
Nothing particularly nefarious happened in Sweden on Friday — or Saturday, for that matter — and Swedes were left baffled.
“Sweden? Terror attack? What has he been smoking? Questions abound,” Carl Bildt, a former prime minister [of Sweden] and foreign minister, wrote on Twitter.
Mr. Trump did not state, per se, that a terrorist attack had taken place in Sweden.
Etymology: From Middle French discursif, from Latin discurro
discursive (comparative more discursive, superlative most discursive)
(of speech or writing) Tending to digress from the main point; rambling.