"Post-truth" defined

It's the Oxford Dictionaries "Word of the Year" for 2016.

After much discussion, debate, and research, the Oxford Dictionaries Word of the Year 2016 is post-truth – an adjective defined as ‘relating to or denoting circumstances in which objective facts are less influential in shaping public opinion than appeals to emotion and personal belief’...

The concept of post-truth has been in existence for the past decade, but Oxford Dictionaries has seen a spike in frequency this year in the context of the EU referendum in the United Kingdom and the presidential election in the United States. It has also become associated with a particular noun, in the phrase post-truth politics. ..

The compound word post-truth exemplifies an expansion in the meaning of the prefix post- that has become increasingly prominent in recent years. Rather than simply referring to the time after a specified situation or event – as in post-war or post-match – the prefix in post-truth has a meaning more like ‘belonging to a time in which the specified concept has become unimportant or irrelevant’. This nuance seems to have originated in the mid-20th century, in formations such as post-national (1945) and post-racial (1971).

Post-truth seems to have been first used in this meaning in a 1992 essay by the late Serbian-American playwright Steve Tesich in The Nation magazine. Reflecting on the Iran-Contra scandal and the Persian Gulf War, Tesich lamented that ‘we, as a free people, have freely decided that we want to live in some post-truth world’.

More at the link.  Post-truth beat out chatbot and coulrophobia, among others.