guardsman

from WordNet (r) 3.0 (2006)

guardsman
    n 1: a soldier who is a member of a unit called `the guard' or
         `guards'

from The Collaborative International Dictionary of English v.0.48

Guardsman \Guards"man\, n.; pl. {Guardsmen}.
   1. One who guards; a guard.
      [1913 Webster]

   2. A member, either officer or private, of any military body
      called Guards.
      [1913 Webster]