Source : Webster's Revised Unabridged Dictionary (1913)

Lutheran \Lu"ther*an\, a. (Eccl. Hist.)
   Of or pertaining to Luther; adhering to the doctrines of
   Luther or the Lutheran Church.

Lutheran \Lu"ther*an\, n. (Eccl. Hist.)
   One who accepts or adheres to the doctrines of Luther or the
   Lutheran Church.

Source : WordNet®

Lutheran
     n : follower of Lutheranism

Lutheran
     adj 1: of or pertaining to Martin Luther or his teachings; "the
            Lutheran doctrine of justification by faith alone"
     2: of or pertaining to or characteristic of the branch of the
        Protestant Church adhering to the views of Luther;
        "Lutheran doctrines"