The Collaborative International Dictionary of English v.0.48:

Limn \Limn\ (l[i^]m), v. t. [imp. & p. p. Limned (l[i^]md); p.
   pr. & vb. n. Limning (l[i^]m"n[i^]ng or l[i^]m"[i^]ng).]
   [OE. limnen, fr. luminen, for enluminen, F. enluminer to
   illuminate, to limn, LL. illuminare to paint. [root]122. See
   Illuminate, Luminous.]
   1. To draw or paint; especially, to represent in an artistic
      way with pencil or brush.
      [1913 Webster]

            Let a painter carelessly limn out a million of
            faces, and you shall find them all different. --Sir
                                                  T. Browne.
      [1913 Webster]

   2. Hence: To picture in words; to describe in graphic terms.
      [PJC]

   3. To illumine, as books or parchments, with ornamental
      figures, letters, or borders.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Limning \Lim"ning\ (l[i^]m"n[i^]ng or l[i^]m"[i^]ng), n.
   The act, process, or art of one who limns; the picture or
   decoration so produced.
   [1913 Webster]

         Adorned with illumination which we now call limning.
                                                  --Wood.
   [1913 Webster]

WordNet (r) 3.0 (2006):

limning
    n 1: a drawing of the outlines of forms or objects [syn:
         delineation, depiction, limning, line drawing]