mot juste vs choice of words

mot juste and choice of words both are nouns.

Word	Noun	Adjective	Verb	Adverb
mot juste	Yes	No	No	No
choice of words	Yes	No	No	No

As nouns, choice of words is a hypernym of mot juste; that is, choice of words is a word with a broader meaning than mot juste:

Other hypernyms of mot juste include diction, phraseology, phrasing, verbiage, wording.

mot juste (noun)	choice of words (noun)
the appropriate word or expression	the manner in which something is expressed in words