Many English words are derived from French words. This shouldn’t be too surprising—the two countries are separated only by a sliver of water, The English Channel (or Chunnel, if you prefer). However, only after the Norman Conquest, in the year 1066, did the two countries become culturally intertwined. Today, many English words reflect this influence. Their origins can be traced to this period, and the few hundred years that ensued (if you check out these words in a dictionary, many of them will have a MF, which stands for Middle French).
ETS probably doesn’t care too much about the historical provenance of these words when it writes the GRE. It does like the fact that with French words you cannot, for the most part, rely on Latin roots (speaking French does help significantly). Oftentimes, if you encounter a French derived word, you will do so at the 600+ level.
Below is but a tiny smattering of GRE words that have made their way into the English lexicon by bounding over the English Channel.
This word literally means cold-blooded. It is defined as calmness and poise, especially in trying situations.
This is a person who has recently acquired wealth, and has therefore risen in class.
Demur is a verb. It means to object. Demur should not be confused with demure, which as an adjective means coy. They both come from around the time of the Norman Conquest (though the Anglophiles may have demurred to use either).
This word is a synonym with parvenu. It comes into the language much more recently, circa 1900.
Let’s see if I can weave them all into a coherent sentence:
Despite the scornful stares from entrenched aristocrats, the parvenu walked blithely about the palace grounds, maintaining his sangfroid and demurring to enter into the petty squabbles that the snobbish were so fond of baiting arrivistes into.