The vowel that swallows its own "n"
French has a trick English doesn't: a vowel can go through its nose. Say a vowel and let the airflow drift up into your nasal passage instead of stopping at a crisp little "n" or "m," and you've made a nasal vowel — one sound, no separate consonant at the end. English speakers meeting these words for the first time almost always add the consonant back in, because English vowels never do this on their own.
The rule
When a French loanword ends in "on," "an," or a similar vowel-plus-nasal combination, Merriam-Webster's own pronunciation often shows that "n" folding into the vowel rather than being pronounced as its own sound — marked with a small raised ⁿ in the dictionary's respelling. "Bon mot" (a clever, well-put remark) is pronounced with one nasal vowel sound for "bon," not two separate sounds "bahn." And the "t" at the end of "mot" stays silent too, the same way French drops most word-final consonants — so the whole phrase collapses to two blended sounds, not four separate letter-sounds.
Hear the difference
Reading every letter the English way — pronouncing "bon" as "bahn" with a full n sound, and pronouncing the silent final "t" in "mot."
Try it yourself
"Denouement" — the winding-up resolution at the end of a story — is another French import Merriam-Webster lists with a nasal vowel near the end. Which approach applies the same rule?