There was the following paragraph in the article titled “Welcome to the post-truth presidency” in Washington Post (December 2).
“As Politico’s Susan Glasser wrote in a sobering assessment of
election coverage for the Brookings Institution, “Even fact-checking
perhaps the most untruthful candidate of our lifetime didn’t work; the
more news outlets did it, the less the facts resonated.” So there is
no reason to think Trump is about to suddenly truth-up. Indeed,
all signs are to the contrary — most glaringly Trump’s
chockfull-of-lies tweet that “I won the popular vote if you deduct the
millions of people who voted illegally.”
Though Google Ngram indicates that the word, “truth up” is current even before or since the beginning of the 19th century with its peak of usage in mid-1800s, neither Oxford nor Cambridge online dictionaries carry this word.
Does “truth up” mean to try to be more truthful and show integrity? What does “truth up” mean? Is it a popular word?
Best Answer
The construction 'something up' is informal American usage, typically when encouraging, exhorting, or castigating someone. Originally seen in "man up" or "cowboy up" (Free Dictionary), respectively meaning:
If I say to someone:
then I'm encouraging and challenging him to be tougher and to finish his studies.
So by extension, 'truth up' means to be more truthful. The sentence you quoted could be written more formally as:
EDIT
There's another example, 'lawyer up', which means to get a lawyer involved in a problem.