top secret

adjective

1

: protected by a high degree of secrecy

a top secret weapon

a top secret meeting

2

a

: containing or being information whose unauthorized disclosure could result in exceptionally grave danger to the nation

top secret messages

compare confidential, secret

b

: of or relating to top secret documents

a top secret clearance

Examples of top secret in a Sentence

The mission is top secret.

Recent Examples on the Web

This book and movie also have one of my favorite Clancy Facts, which is that Tom revealed a top secret, silent navigation technology that caused a minor stir in the world of military-industrial-complex boat guys. —Literary Hub, Literary Hub, 13 Apr. 2026

According to the complaint, Williams worked for the Army between 2010 and 2016 after serving as a contractor and previously enlisting, and held a top secret security clearance. —Jacob Rosen, CBS News, 9 Apr. 2026

The stunt was kept top secret, even from some of Kelly's own staff. —Meredith Kile, PEOPLE, 9 Apr. 2026

The dress was top secret—Burton didn't even tell her mom. —Christina Perrier, InStyle, 12 Mar. 2026

Word History

First Known Use

1942, in the meaning defined at sense 1

Kids Definition

top secret

adjective

1

: protected by a high degree of secrecy

a top secret meeting

2

: containing information that is very important to the safety and defense of a nation

top secret messages