Douglas Harper's Etymology Dictionary
"pedantic woman, woman aiming at refined delicacy of language and taste" (1727), from French précieuse, noun use of fem. of précieux (see precious (adj.)); especially as lampooned in Molière's comedy "Les Précieuses ridicules" (1659).
Wikipedia
Précieuse is the sword of Baligant, the Saracen king in the French epic The Song of Roland.
Baligant allegedly named his sword in response to hearing that Charlemagne's sword had a name. Throughout the epic, there are several contrasts between the two, with Baligant being portrayed as a foolish counterpart to Charlemagne. Baligant felt inferior, and so named his sword with a similar name.
Usage examples of "precieuse".
He did not yet know that the precieuses collected love letters as they did geegaws and bangles, more interested in their conceits than in their author.
When it was learned that d’lgby, actually as Bouquin-quant’s envoy, had fought a privateering war against Spain, the universe of the precieuses found him fascinating.