Not publicly or generally known; secret
Excluding or unavailable to certain groups:
Secret, not spoken of (spoken of only in hushed whispers between insiders).
Of or pertaining to classified advertising
Find another word for top-secret. In this page you can discover 10 synonyms, antonyms, idiomatic expressions, and related words for top-secret, like: confidential, secret, restricted, kept quiet, hush-hush, classified, highly classified, supersecret, under security restrictions and under-wraps.