From BiblePortal Wikipedia

King James Dictionary [1]

PRIV'Y, a. L. privus. See Private.

1. Private pertaining to some person exclusively assigned to private uses not public as the privy purse the privy confer of a king. 2. Secret clandestine not open or public as a privy attempt to kill one. 3. Private appropriated to retirement not shown not open for the admission of company as a privy chamber.  Ezekiel 21 4. Privately knowing admitted to the participation of knowledge with another of a secret transaction.

He would rather lose half of his kingdom than be privy to such a secret.

Myself am one made privy to the plot.

His wife also being privy to it.  Acts 5

5. Admitted to secrets of state. The privy council of a king consists of a number of distinguished persons selected by him to advice him in the administration of the government.

A privy verdict, is one given to the judge out of court, which is of no force unless afterward affirmed by a public verdict in court.

PRIV'Y, n. In law, a partaker a person having an interest in any action or thing as a privy in blood. Privies are of four kinds privies in blood, as the heir to his father privies in representation, as executors and administrators to the deceased privies in estate, as he in reversion and he in remainder donor and donee lessor and lessee privy in tenure, as the lord in escheat.

1. A necessary house.

Privy chamber, in Great Britain, the private apartment in a royal residence or mansion. Gentlemen of the privy chamber are servants of the king who are to wait and attend on him and the queen at court, in their diversions, &c. They are forty eight in number, under the lord chamberlain.

Webster's Dictionary [2]

(1): ( n.) A necessary house or place; a backhouse.

(2): ( a.) Of or pertaining to some person exclusively; assigned to private uses; not public; private; as, the privy purse.

(3): ( a.) Secret; clandestine.

(4): ( a.) Appropriated to retirement; private; not open to the public.

(5): ( a.) Admitted to knowledge of a secret transaction; secretly cognizant; privately knowing.

(6): ( n.) A partaker; a person having an interest in any action or thing; one who has an interest in an estate created by another; a person having an interest derived from a contract or conveyance to which he is not himself a party. The term, in its proper sense, is distinguished from party.

Vine's Expository Dictionary of NT Words [3]

1: Σύν (Strong'S #4862 — Preposition — sunoida — soon )

see Know , No. 6