clandesti-, clandest- +

1. Used as an alternative to clandestine, meaning "secret"; however, it could not be found in any dictionary, but it is widely used; especially, on the World Wide Web.
2. Etymologically, it should mean "becoming more secret" because -escent is a suffix signifying "beginning, beginning to be" or "becoming".

1. Needing to be concealed, usually because it is illegal or unauthorized.
2. Conducted with or marked by hidden aims or methods: "Most nations conduct clandestine intelligence operations."
3. Kept or done in secret, often in order to conceal an illicit or improper purpose.
3. Etymology: from about 1566, from Latin clandestinus, "secret, hidden"; from clam, "secretly"; which came from the basic element of celare, "to hide, to conceal".

Generally a reference to chemistry carried out in illegal drug laboratories, but it can also include any kind of laboratory operation carried on in secret.

1. Something done secretly; privately; in secret.
2. Conducted with or marked by hidden aims or methods.

Marked by, held in, or conducted with secrecy; surreptitiousness; that is, done, made, or acquired by stealth (intended to escape observation).

A government, or military, intelligence operation so planned and executed as to insure concealment.

Characterized by, done in, or executed with secrecy or concealment; especially, for purposes of subversion or deception; private or surreptitious.

Done openly without being secretive.

A clandestine, or hidden, voice; a whisper.