Secret

adjective
1.
done, made, or conducted without the knowledge of others:
secret negotiations.
2.
kept from the knowledge of any but the initiated or privileged:
a secret password.
3.
faithful or cautious in keeping confidential matters confidential; close-mouthed; reticent.
4.
designed or working to escape notice, knowledge, or observation:
a secret drawer; the secret police.
5.
secluded, sheltered, or withdrawn:
a secret hiding place.
6.
beyond ordinary human understanding; esoteric.
7.

bearing the classification secret.
limited to persons authorized to use information documents, etc., so classified.

noun
8.
something that is or is kept secret, hidden, or concealed.
9.
a mystery:
the secrets of nature.
10.
a reason or explanation not immediately or generally apparent.
11.
a method, formula, plan, etc., known only to the initiated or the few:
the secret of happiness; a trade secret.
12.
a classification assigned to information, a document, etc., considered less vital to security than top-secret but more vital than confidential, and limiting its use to persons who have been cleared, as by various government agencies, as trustworthy to handle such material.
Compare classification (def 5).
13.
(initial capital letter) Liturgy. a variable prayer in the Roman and other Latin liturgies, said inaudibly by the celebrant after the offertory and immediately before the preface.
Idioms
14.
in secret, unknown to others; in private; secretly:
A resistance movement was already being organized in secret.
adjective
1.
kept hidden or separate from the knowledge of others related adjective cryptic
2.
known only to initiates: a secret password
3.
hidden from general view or use: a secret garden
4.
able or tending to keep things private or to oneself
5.
operating without the knowledge of outsiders: a secret society
6.
outside the normal range of knowledge
noun
7.
something kept or to be kept hidden
8.
something unrevealed; mystery
9.
an underlying explanation, reason, etc, that is not apparent: the secret of success
10.
a method, plan, etc, known only to initiates
11.
(liturgy) a variable prayer, part of the Mass, said by the celebrant after the offertory and before the preface
12.
in the secret, among the people who know a secret
secret