The Collaborative International Dictionary of English v.0.48:

Unsentimental \Unsentimental\
   See sentimental.

WordNet (r) 3.0 (2006):

unsentimental
    adj 1: facing facts or difficulties realistically and with
           determination [syn: tough-minded, unsentimental]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "unsentimental":
   down-to-earth, earthy, hard, hard-boiled, hardheaded,
   matter-of-fact, positivistic, practical, practical-minded,
   pragmatic, rational, realist, realistic, reasonable, sane,
   scientific, scientistic, secular, sensible, sober, sober-minded,
   sound, sound-thinking, straight-thinking, unideal, unidealistic,
   unromantic, worldly