The vertical edge of a sail that is closest to the direction of the wind.

“By easing the halyard, the luff of the sail was made to sag to leeward.”

The act of sailing a ship close to the wind.

The roundest part of a ship's bow.

(of a sail) To shake due to being trimmed improperly.

(of a boat) To alter course to windward so that the sails luff. (Alternatively luff up)

To let out (a sail) so that it luffs.