The Collaborative International Dictionary of English v.0.48:

Engineer \En`gi*neer"\, n. [OE. enginer: cf. OF. engignier, F.
   ing['e]nieur. See Engine, n.]
   1. A person skilled in the principles and practice of any
      branch of engineering; as, a civil engineer; an electronic
      engineer; a chemical engineer. See under Engineering, n.
      [1913 Webster +PJC]

   2. One who manages as engine, particularly a steam engine; an
      engine driver.
      [1913 Webster]

   3. One who carries through an enterprise by skillful or
      artful contrivance; an efficient manager. [Colloq.]
      [1913 Webster]

   Civil engineer, a person skilled in the science of civil
      engineering.

   Military engineer, one who executes engineering works of a
      military nature. See under Engineering.
      [1913 Webster]

WordNet (r) 3.0 (2006):

military engineer
    n 1: a member of the military who is trained in engineering and
         construction work [syn: army engineer, military
         engineer]