Definition of "top secret" [top• sec•ret]

• Information classified at the highest level of sensitivity by a government, based on an assessment that it would cause exceptionally grave damage to national security if disclosed. (adjective)
• A level of security clearance needed to access such information. (adjective)
• Pertaining to any especially sensitive closed-room activities. (adjective)

Wiktionary.org : Text is available under the Creative Commons Attribution-ShareAlike License

• "Moody also intercepted top secret mail and once came close to capturing William Livingston, the patriot governor of New Jersey."
• "ON AUGUST 13, 1956, with Rakosi already gone, and the city buzzing with new freedoms and a tentative self-confidence, an AVO officer named Rezso Kovacs, in a top secret memorandum addressed to the minister of the interior, declared: The crimes committed by Dr. Endre Marton—treason and espionage—are sufficiently demonstrated by evidence to prompt us not to recommend that his sentence be lowered."
• "And the Par-Con deal was top secret to the Inner Court only."