Glomar response

noun1

1. •
   A response by a US government agency (etc) that it can "neither confirm nor deny" the existence of (secret) information which has been asked for.

   • As an alternative basis for its holding, the District Court held that the CIA Information Act, 50 U.S.C. § 431, permits a Glomar response only when the FOIA request relates to a covert activity. — 1993