Other forms: privies
Privy means sharing in a secret with a few others. Privy to the plan, not privy to it, privy to the discussions.
It is always followed by to, and it means having been let in rather than having found out: not privy to the decision means nobody told you. In Britain the Privy Council is a formal body of advisers to the Crown, and privy purse is the monarch's private income. As a noun, a privy is an outdoor toilet, which is the same word for the same reason — a private place.
1adjectiveprivySharing in a secret with a few others.
“Only a few senior managers were privy to the plans for the merger.”
2nounoutdoorAn outdoor toilet.
“In the old cottage, the only toilet was a privy at the bottom of the garden.”
privy is a state of sharing a secret.
Old French privé comes from Latin privatus, deprived or set apart. Private is the same word borrowed again later, which is why privy and private mean such different things now.
Latin
prīvātus — deprived
Old French
privé — private
Middle English
pryvy
English, today
privy
Built from
From Middle English pryvy, prive, from Old French privé (“private”), from Latin prīvātus (“deprived”), perfect passive participle of prīvō (“to bereave, deprive; to free, release”). a doublet of private.
Etymology from Wiktionary, CC BY-SA