Meaning

noun a room or building equipped with one or more toilets

noun a small outbuilding with a bench having holes through which a user can defecate

adjective hidden from general view or use

originFrom Middle English pryvy, prive, from Old French privé (“private”), from Latin prīvātus (“deprived”), perfect passive participle of prīvō (“to bereave, deprive; to free, release”). Doublet of private.

Etymology from Wiktionary, CC BY-SA 3.0