The Collaborative International Dictionary of English v.0.48:

Machinist \Ma*chin"ist\, n. [Cf. F. machiniste.]
   1. A constructor of machines and engines; one versed in the
      principles of machines.
      [1913 Webster]

   2. One skilled in the use of machine tools.
      [1913 Webster]

   3. A person employed to shift scenery in a theater.
      [1913 Webster]

WordNet (r) 3.0 (2006):

machinist
    n 1: a craftsman skilled in operating machine tools [syn:
         machinist, mechanic, shop mechanic]