The Collaborative International Dictionary of English v.0.48:

down-to-earth \down-to-earth\ adj.
   facing reality squarely; guided by practical experience and
   observation rather than theory. Opposite of idealistic,
   unrealistic, impractical, and pie-in-the-sky.

   Syn: hardheaded, hard-nosed, practical, pragmatic.
        [WordNet 1.5] Downtrod

WordNet (r) 3.0 (2006):

down-to-earth
    adj 1: sensible and practical; "has a straightforward down-to-
           earth approach to a problem"; "her earthy common sense"
           [syn: down-to-earth, earthy]

Moby Thesaurus II by Grady Ward, 1.0:

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