Oh, and panache is French, so it’s a slightly lengthened “ash” at the end.
And “nosh” is well established English slang for food hence the TV show Posh Nosh
People understand what ‘octopi’ means, which makes it a word in English. There’s a reason English is the universal language, and it’s not stodgy rigidity of form.
Don’t feel too bad, my daughter still gets a hard time about “Hercules Portrait” (Hercule Poirot) 
All Greek works have a hard C, not soft.
Yeah, that one is not pronounced AT ALL the way it is written. “Onwee”.
Yeah, I can live with Octopodes, and that is how i would pronounce it. But octopi is right out.
I may be talking out of my ass here, not knowing any Greek and only knowing about Greek letters from math and physics, but wouldn’t the Greek first letter of the Greek word “chimera” be χ (chi), and wouldn’t it be pronounced as the letter combination “ch” in German, for example in “ich”? Because that’s a very different sound than a hard ‘c’ in English.
Only SKOOkill is correct. And I grew up just a couple miles from it. Between it and Cobb’s Creek (same vowel as in been) Park.
One thing I have a problem getting my mind around is that Canadians pronounce been as bean and intestine so that the last syllable rhymes with line.
Bon mot…pronounced “bun-moe”.
Defined as a clever, witty remark.
Never heard in conversation.
I think Diane used to say it that way on Cheers. Every other time I’ve heard it it was pronounced phonetically.
Take the word rendezvous.
The obvious way to figure out how to pronounce is by splitting it into three parts:
ren
dez
vous [note the same “ous” as in obvious.]
Strangely enough my junior high school teacher said I was pronouncing it incorrectly!
I don’t really have any words like this, because I tend to look up the pronunciation whenever I read a word I don’t know. There are quite useful resources for this, including forvo, howjsay, and wiktionary (sometimes).
But I’ve had several fun situations with friends:
antelope pronounced with 4 syllables
hippopotamus pronounced with the emphasis on the second last syllable
epitome pronounced with 3 syllables
hyperbole pronounced with 3 syllables
vague pronounced to rhyme with bag
(sorry, all the comments made me forget that the point of this thread was about words unused in conversation, rather than words pronounced incorrectly because you’ve only seen them written)
Flanders and Swann did this in The Hippopotamus Song, making the A long, and rhyming it with ignoramus.
The only ones I have trouble with are Bachtrachian, Cacodaemoniacal, Ichthyic and Lucubration, although I generally have some clue how to say them. A bit of ancient Greek and Latin goes a long way.
My favourite word in Lovecraft is ‘congeries’, which he uses to mean ‘a mass of bubbles’. Actually it means ‘a disorderly mass of anything’, and comes from Latin, so I’m guessing it is pronounced ‘Kon-ger-is’, but I might be wrong.
Well, yeah, but if you’ve only seen a word written, then in your experience, it’s not used in conversation.
In an apocryphal signal between them (they served together in WWII in the Med I think), HMS Penelope was “Pennyloap”, and HMS Antelope was “Antellopee”.
I believe the “huh” is because you put the emPHAsis on the wrong syLABle. 
One word I had read but rarely ever heard spoken actually came up on Jeopardy today. Sidereal is not pronounced as “side-real” but “sai-dee-ree-al.”
Nitpick: sigh-DEER-ee-uhl
I’ve never understood how anyone tells the difference between sigh-DEER-ee-uhl and sigh-DEE-ree-uhl.
What indicates whether the consonant sound (R, in this case) is in the 2nd or 3rd syllable?
I saw another one last night in The Road (a book for masochists.)
Bivouacked. It came up a lot in the Everest books too.
C’est vrai, bébé … because the French swallow so many sounds (most notably, the last letter of almost every word).
I believe that everyone should learn to pronounce words that English stole (or is it… an homage?) from French. And nothing beats hearing them said in French.
We can’t even transliterate them into English, because we can’t write those wonderful sounds that resonate in the back of the mouth…
Bon mot…pronounced “bun-moe”.
But if you were to say that like a hot dog bun, you’d sound like an Ugly American. It’s really more like “bohhh…(with the merest hint of a throaty n in there)-moh”.
.
eta: “Hot dog” in French? Le hot dog!