Source : Webster's Revised Unabridged Dictionary (1913)

Physicist \Phys"i*cist\, n.
   One versed in physics.

   2. (Biol.) A believer in the theory that the fundamental
      phenomena of life are to be explained upon purely chemical
      and physical principles; -- opposed to vitalist.

Source : WordNet®

physicist
     n : a scientist trained in physics