pong

Etymology 1

Probably from Romani pan (“to stink”).

noun

1. (UK, Australia, New Zealand, slang) A stench, a bad smell.
   1992, Bryce Courtenay, Tandia, Volume 1, 2011, Read How You Want, page 109, She sniffed, squiffing up her nose. ‘What a pong! Do they all smell like this?’
   I can remember calling round once and when she answered the door I was greeted by an unmistakable, noxious pong. “I can smell gas!” I said. “Oh, have I left the ring on?” she asked vaguely. 1998, Catherine Fox, Heaven′s Scent: Third Way, page 13
   2000, Susan Sallis, 2011, unnumbered page, ‘I see what you mean about the pong. I couldn′t smell it on myself but I can smell it on you!’
   If you want to empty a crowded room strong body pong will usually do the trick. 2009, Martin Fine, The Devil′s Fragrance, page 109

verb

1. (UK, Australia, New Zealand, slang) To stink, to smell bad.
   1997, Taufiq Ismail, David M. E. Roskies (translator and editor), Stop Thief!, Black Clouds Over the Isle of Gods and Other Modern Indonesian Short Stories, page 97, On she walked at a crawling pace, ponging of sweat, drops of mucus and blood falling between her feet.
   2009, Susan Brocker, Saving Sam, HarperCollins, New Zealand, unnumbered page, The place ponged, like the smell of stale cat pee.
   […]That toothless bloke ponged. Couldn′t you smell him? He smelled like a bloody pub floor at closing time. 2010, Robin Easton, Naked in Eden: My Adventure and Awakening in the Australian Rainforest, page 63
   2011, Victor Pemberton, We′ll Sing at Dawn, 2012, eBook, Headline Publishing, unnumbered page, […] and this evening, Eileen Perkins′s daughter Rita ponged with the smell of cheap carbolic soap, after a late-afternoon visit to the public baths down Hornsey Road.
2. (slang, theater, derogatory) To deliver a line of a play in an arch, suggestive or unnatural way, so as to draw undue attention to it.
3. (slang, theater, intransitive) To invent a line of dialogue when one has forgotten the actual line.
   […] and the “good old crusted” actor, forgetting the lines of the author, used without compunction to cover his discomfiture by inventing a text of his own–an achievement known as "ponging." 2016, Jim Davis, European Theatre Performance Practice, 1750–1900

Etymology 2

From ping, via the pairing of ping-pong.

noun

1. (networking) A packet sent in reply to a ping, thereby indicating the presence of a host.

Etymology 3

noun

1. (mahjong) Alternative form of pung