"curl or lock of hair over the forehead," by 1890, originally a style among soldiers, a word of unknown origin. Perhaps connected with quiff "a puff or whiff of tobacco smoke" (1831, originally Southern U.S.), which is held to be a variant of whiff (n.).
also grape-shot, 1747, from grape + shot (n.). So called for its appearance. Originally simply grape (1680s), a collective singular. The whiff of grapeshot was popularized in English from 1837, from Carlyle's history of the French Revolution (in which book it was a chapter title). It seems to be his.
The Nobles of France, valorous, chivalrous as of old, will rally round us with one heart;—and as for this which you call Third Estate, and which we call canaille of unwashed Sansculottes, of Patelins, Scribblers, factious Spouters,—brave Broglie, "with a whiff of grapeshot (salve de canons)," if need be, will give quick account of it. [Carlyle, "French Revolution"]
early 15c., from Old French ambre gris "gray amber," "a wax-like substance of ashy colour, found floating in tropical seas, a morbid secretion from the intestines of the sperm-whale. Used in perfumery, and formerly in cookery" [OED], via Medieval Latin from Arabic 'anbar (see amber). Its origin was known to Constantinus Africanus (obit c. 1087), but it was a mystery in Johnson's day, and he records nine different theories; "What sort of thing is Ambergrease?" was a type of a puzzling question beyond conjecture. King Charles II's favorite dish was said to be eggs and ambergris [Macauley, "History of England"].
Praise is like ambergris; a little whiff of it, by snatches, is very agreeable; but when a man holds a whole lump of it to his nose, it is a stink and strikes you down. [Pope, c. 1720]
French gris is from Frankish *gris or some other Germanic source (cognates: Dutch grijs, Old High German gris; see gray (adj.)).