to leave or depart slyly, without saying anything; or obtaining permission.
John Camden Hotten. The Slang Dictionary (1913)
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to go off without taking leave of the company: a saying frequently applied to persons who have run away from their creditors.
Francis Grose. 1811 Dictionary of the Vulgar Tongue
► uses
Uses:
But as I was certain I should not be allowed to leave the enclosure, my only plan was to take French leave and slip out when nobody was watching, and that was so bad a way of doing it as made the thing itself wrong. But I was only a boy, and I had made my mind up.
Robert Louis Stevenson. Treasure Island (1883)
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As for Ditton, after all his courting, and his compliment, he stole away an Irishman's bride, and took a French leave of me and his master; but I vally not his going a farting; but I have had hanger on his account
Tobias Smollett. The Expedition of Humphry Clinker (1771)
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"[...] give me leave, sir—the French have attained to a wonderful skill in making compositions of this kind."
Tobias Smollett. The Adventures of Roderick Random (1749)