It’s a very good question, with both a serious answer and one not so serious.
One meaning is ‘roc, the bird of legend’. Something like that is to be expected.
A less traditional telling is that, back in 2012, ‘Peng’ was submitted to The Collins English Dictionary as a new word suggestion. It would be used to describe a person of exceptional goodness and beauty or, better still, anything that was simply very, very good.
Suggested examples of usage are ‘This pizza is so nice, it tastes peng’, ‘Your tee shirt is really peng’ and ‘That’s some peng weed, man’.
Seven years later, the young wag who submitted the word to Collins, a certain ‘hmpeng1’, is still awaiting its approval. He – it must presumed to be a young scallywag with a great sense of humour – might be waiting a while longer, but must surely dine out regularly on it still coming up tops in a Google search on ‘The Meaning of Peng’.