Webster's Revised Unabridged Dictionary · 1913

Secret

Secret , adjective

[French secret (compare Sp. & Portuguese secreto, Italian secreto, segreto), from Latin secretus, past participle of secernere to put apart, to separate. See Certain, and compare Secrete, Secern.]

1.
Hidden; concealed; as, secret treasure; secret plans; a secret vow. — Shakespeare
The secret things belong unto the Lord our God; but those things which are revealed belong unto us. — Deut. xxix. 29
2.
Withdrawn from general intercourse or notice; in retirement or secrecy; secluded.
There, secret in her sapphire cell, He with the Nais wont to dwell. — Fenton
3.
Faithful to a secret; not inclined to divulge or betray confidence; secretive. [Rare]
Secret Romans, that have spoke the word, And will not palter. — Shakespeare
4.
Separate; distinct. [Obsolete]
They suppose two other divine hypostases superior thereunto, which were perfectly secret from matter. — Cudworth

Secret , noun

[French secret (compare Pr. secret, Sp. & Portuguese secreto, Italian secreto, segreto), from Latin secretum. See Secret, a.]

1.
Something studiously concealed; a thing kept from general knowledge; what is not revealed, or not to be revealed.
To tell our own secrets is often folly; to communicate those of others is treachery. — Rambler
2.
A thing not discovered; what is unknown or unexplained; a mystery.
All secrets of the deep, all nature's works. — Milton
3.
The parts which modesty and propriety require to be concealed; the genital organs.
Bread eaten in secret is pleasant. — Bible (KJV) - Proverb ix. 17
Collocations (1)
In secret , in a private place; in privacy or secrecy; in a state or place not seen; privately.

Secret , transitive verb

To keep secret. [Obsolete] — Bacon