luff (n.) Look up luff at Dictionary.com
c.1200, in sailing, from Old French lof "spar," or some other nautical device, "point of sail," also "windward side," probably from Germanic (compare Middle Dutch lof "windward side of a ship" (Dutch loef), which might also be the direct source of the English word), from Proto-Germanic *lofo (cognates: Old Norse lofi, Gothic lofa "palm of the hand," Danish lab, Swedish labb "paw"), from PIE *lep- "to be flat" (see glove). As a verb from late 14c., from the noun.