The Collaborative International Dictionary of English v.0.48:

Rigger \Rig"ger\, n.
   1. One who rigs or dresses; one whose occupation is to fit
      the rigging of a ship.
      [1913 Webster]

   2. A cylindrical pulley or drum in machinery. [R.]
      [1913 Webster]

   3. (Painting) A long slender, and pointed sable brush for
      making fine lines, etc.; -- said to be so called from its
      use by marine painters for drawing the lines of the
      rigging.
      [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

rigger
    n 1: someone who rigs ships
    2: a long slender pointed sable brush used by artists [syn:
       rigger, rigger brush]
    3: someone who works on an oil rig [syn: rigger, oil rigger]
    4: a sailing vessel with a specified rig; "a square rigger"