Definition of "luff"

(nautical) The vertical edge of a sail that is closest to the direction of the wind.  quotations  examples

(nautical) The act of sailing a ship close to the wind.  examples

(nautical) The roundest part of a ship's bow.  examples

(nautical) The forward or weather leech of a sail, especially of the jib, spanker, and other fore-and-aft sails.  examples

(nautical, of a sail, intransitive) To shake due to being trimmed improperly.  quotations  examples

(nautical, of sailing vessels, intransitive) To bring the ship's head up closer to the wind. (Alternatively luff up)  quotations  examples

(nautical, transitive) to let out (a sail) so that it luffs.  examples

(mechanical) To alter the vertical angle of the jib of a crane so as to bring it level with the load.  quotations  examples