French leave

English

From French (adjective) +‎ leave (noun), apparently from a French custom, already recorded in the 18th century, of leaving from receptions or other events without formally announcing one’s departure to the host or hostess.^[1] Compare Spanish irse a la francesa and Portuguese sair à francesa (“go in the French manner”) but also the otherwise ubiquitous attribution of this behaviour to the English as with French filer à l’anglaise (“leave in the English manner”), Italian filarsela all'inglese, Polish wyjść po angielsku, etc.

French leave (uncountable) (idiomatic, informal, dated)

A departure taken quietly and unnoticed, without asking for permission or informing anyone. [from mid 18th c.]
Synonyms: French exit; (figurative) AWOL, disappearing act, Irish goodbye
- 1771, [Tobias Smollett], “To Mrs. Mary Jones, at Brambleton-hall”, in The Expedition of Humphry Clinker […], volume II, London: […] W. Johnston, […]; and B. Collins, […], →OCLC, page 226:
  As for Ditton, after all his courting, and his compliment, he ſtole avvay an Iriſhman's bride, and took a French leave of me and his maſter; […]
(specifically, chiefly military, euphemistic) Desertion or temporary absence from duty or service without permission; absence without leave, AWOL.
- 2010, William Marvel, The Great Task Remaining: The Third Year of Lincoln’s War, page 10:
  he may have felt a particular need to mitigate the responsibility of those who shirked their duty, for as he wrote that letter he had just returned from French leave himself.

departure taken quietly and unnoticed

Chinese:
Mandarin: 不辭而別／不辞而别 (zh) (bùcí'érbié)
Finnish: liukeneminen (fi), häipyminen (fi), haihtuminen (fi)
French: filer à l’anglaise (fr) (take English leave)
German: (dated, may not be understood) französischer Abschied m (literally “French farewell”); (unidiomatic, but now preferable) grußloser Abschied, heimliche Abfahrt etc., einen Polnischen machen
Hungarian: angolosan távozik (hu) (take English leave)
Polish: wyjście po angielsku n (take English leave)
Portuguese: saída à francesa f
Russian: ухо́д по-англи́йски m (uxód po-anglíjski) (take English leave)
Spanish: despedida a la francesa f
Swedish: bondpermission (sv) c, (colloquially) bondpermis (sv) c

desertion or temporary absence from duty or service without permission — see AWOL