en clair

Of the transmission of a signal

• So it was that Chartier was forced to telegramme en clair, meaning that his contacts with Vichy were open for all to read and were thus largely confined to run-of-the-mill information.2003, Nicholas Atkin, “Agents consulaires or agents provocateurs?”, in The Forgotten French: Exiles in the British Isles, 1940–44, Manchester; New York, N.Y.: Manchester University Press, →ISBN, chapter 4 (The surveillance of exile: the Vichy consulates), page 158:
• As per Berchtold's instructions, Giesl stopped in the border town of Semlin and wired the news immediately, en clair, such that Tisza, in Budapest, learned of Serbia's rejection even before 7 PM.2014, Sean McMeekin, 7/1/2014: Countdown to War, page 201: