Definition of luffs:
(n) :
(nautical) The act of sailing a ship close to the wind.
(v) :
(nautical, of sailing vessels, intransitive) To bring the ship's head up closer to the wind. (Alternatively luff up)
(n) :
(nautical) The vertical edge of a sail that is closest to the direction of the wind.
(v) :
(nautical, of a sail, intransitive) To shake due to being trimmed improperly.
(v) :
(nautical, transitive) to let out (a sail) so that it luffs.
(n) :
(nautical) The forward or weather leech of a sail, especially of the jib, spanker, and other fore-and-aft sails.