--oon words

The ending -oon is a rather funny feature of English. It doesn’t really sound English at all, and on further investigation, in most cases it is not from English but a mispronunciation of the ending -one (onay) in Italian or another Romance language.

Doubloon: from Spanish doblon, a 17th-century gold coin that was called a doubloon because it was double the value (twice the value) of another gold coin, the pistole.

The “doblon” came from Latin duplus, double. I suppose someone trying to bring “doblon” into English just didn’t know what to do with the second “o” and pronounced it “oo.”

However, there are several instances like this, where English borrowed a Latin word and mispronounced the ending “oon.”

Spittoon

A spittoon is a jar or other receptacle for spit (saliva).
People chewing tobacco (or otherwise just needing
to spit) used to use the spittoon. A spittoon also had a more
classy name, the cuspidor. As it turns out, though, the “spi” part of cuspidor traces back to the same humble roots as “spit” itself: Latin spuere. I was delighted to discover (okay, I’m weird) that “spew” comes from the same word. I had nothing in my mouth at the time, so I was unable to spew with joy, but I would’ve if I could’ve.

Balloon

“Balloon” is another charming mispronunciation from either French “ballon” or (I prefer) Italian “pallone.” Here the “-one” (“onay”) is an additive meaning “big.” So a “balloon” is a big ball. The word “ball” goes all the way back to Proto Indo-European as *bhal, meaning “a swelling.” So you could have asked an Indo-European kid for a ball 10,000 years ago and he would have understood you (if he had a ball).

Maroon

Maroon, again, is a mispronunciation, this time from “marron,” or “brown.” We in English have adopted the word but changed its color to a deep red rather than the brown it still is in French, Spanish, and Italian.
I don’t know about Portuguese or Romanian, though.