French leave definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
an unauthorized, unnoticed, or unceremonious departure; act of leaving secretly or in haste
Origin: ; from 18th-c. custom, prevalent in France, of leaving receptions without taking leave of the host or hostess
French leave definition by American Heritage Dictionary
An informal, unannounced, or abrupt departure.
Origin: From the 18th-century French custom of leaving without saying goodbye to the host or hostess.