noun

• (UK, Ireland, Commonwealth, 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?’"

verb

• (UK, Ireland, Commonwealth, 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."
• (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.
• (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.""

noun

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

noun

• (mahjong) Alternative form of pung.