Faire du gringue

Literally: To make some gringue

Example: “Toute la soirée, il a fait du gringue à la voisine de table.” — All evening, he kept making passes at the woman seated next to him.

English equivalent: To make a pass at someone

Origin: Gringue was bread. In the middle of the 16th century grignon — from grigner, the root of grignoter (to nibble) — was a regional word for a piece of bread, and gringue derives from it, serving as a word for bread through the second half of the 19th century. Aristide Bruant has faire du gringue at the very start of the 20th meaning to try to please, and within ten years it had sharpened into pressing courtship. How bread got there is the obvious question, and the only answer offered — by Gaston Esnault, with no certainty at all — is a link to the older faire des petits pains pour quelqu'un (to make little breads for someone), which meant first to make oneself agreeable in order to bait, and then simply to court.