sack up v. to become bold, courageous, or forthright; to nut up, man up. (source: Double-Tongued Dictionary)
Further reading
It was a dark and stormy night. So begins the long and increasingly convoluted prose of Edwards Bulwer-Lytton’s best-known novel. Today the annual Bulwer-Lytton Contest asks contestants for fanciful first sentences that are similarly...
How do social media algorithms shape the way we communicate? A new book argues that the competition for clicks is changing the way we speak and write, from the so-called “YouTube accent” to the surprising evolution of the word preppy. Also: A...