A zing is that sharp little snap in a comment, a proper witty jab that lands clean. It can also mean a bit of extra spark or pep, like a song, outfit, or party having more energy than expected. Not full-on insult territory, more clever and cutting with style. Honestly, a good zing is basically social seasoning.
"He served beige pasta again and she goes, This tastes like a funeral for flavour. Everyone lost it. I nearly choked on my brew, mate. That was a zing and a half."