Please don’t ask how this started, because I can’t remember. Anyhow, the phrase chin chin, admittedly a little outmoded now, popped into my head. There are two distinct meanings in English. One is an alternative for “Cheers!” when drinking. This is also used, as cin cin or cincin, in Italian. I don’t know any other languages that use it.
The other meaning is “Goodbye”. It is used thus in the WW1 song Goodbye-ee:
Wipe the tear, baby dear, from your eye-ee,
Tho’ it’s hard to part I know,
I’ll be tickled to death to go.
Don’t cry-ee, dont sigh-ee,
There’s a silver lining in the sky-ee,
Bonsoir, old thing, cheerio, chin, chin,
Nah-poo, toodle-oo, Goodbye-ee.
In case you are wondering, Nah-poo is obsolete army slang for “finished”. It is a corruption of French il n’y (en) a plus. In case you are still wondering, toodle-oo is also an old-fashioned farewell greeting, but of unknown origin. It has a variant toodle-pip. You may well have come across some of these words if you have read any of the Jeeves and Wooster stories by P.G. Wodehouse.
Well, back to chin chin. I was mightily surprised to find that its origin is the Chinese word qǐng tɕiŋ, which means “please” or “to invite”.