information known only to a special group; "the secret of Cajun cooking"
something that should remain hidden from others (especially information that is not to be passed on); "the combination to the safe was a secret"; "he tried to keep his drinking a secret"
the next to highest level of official classification for documents
not expressed; "secret (or private) thoughts"
indulging only covertly; "a secret alcoholic"
communicated covertly; "their secret signal was a wink"; "secret messages"
not open or public; kept private or not revealed; "a secret formula"; "secret ingredients"; "secret talks"
difficult to penetrate; incomprehensible to one of ordinary understanding or knowledge; "the professor's lectures were so abstruse that students tended to avoid them"; "a deep metaphysical theory"; "some recondite problem in historiography"
so exceedingly large or extensive as to suggest a giant or mammoth; "a gigantic redwood"; "gigantic disappointment"; "a mammoth ship"; "a mammoth multinational corporation"
so great in size or force or extent as to elicit awe; "colossal crumbling ruins of an ancient temple"; "has a colossal nerve"; "a prodigious storm"; "a stupendous field of grass"; "stupendous demand"