En svensk tiger

Beredskapsmuseet's sign of En Svensk Tiger.
The famous propaganda poster warned Swedes to be wary of speaking.

En svensk tiger (Swedish: [ɛn ˈsvɛnːsk ˈtǐːɡɛr]) was a slogan and an image that became part of a propaganda campaign in Sweden during World War II. Its goal was to prevent espionage by encouraging secrecy.