The Collaborative International Dictionary of English v.0.48:

Militarist \Mil"i*ta*rist\, n.
   1. A military man. [Obs.] --Shak.
      [1913 Webster]

   2. A person having a strong spirit of militarism, in senses 3
      or 4.
      [PJC]

WordNet (r) 3.0 (2006):

militarist
    n 1: a person who advocates war or warlike policies [syn:
         militarist, warmonger]