The runner-up is “alt-right.”From the Oxford Dictionary blog:
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.
Post-truth has gone from being a peripheral term to being a mainstay in political commentary, now often being used by major publications without the need for clarification or definition in their headlines.