unadventurous

from WordNet (r) 3.0 (2006)

unadventurous
    adj 1: lacking in boldness [ant: {adventuresome}, {adventurous}]

from The Collaborative International Dictionary of English v.0.48

Unadventurous \Unadventurous\
   See {adventurous}.

from Moby Thesaurus II by Grady Ward, 1.0

28 Moby Thesaurus words for "unadventurous":
      canny, careful, cautious, circumspect, deliberate, discreet,
      gingerly, guarded, heedful, hesitant, judicious,
      leaving out nothing, mindful, noncommittal, on guard,
      overlooking no possibility, pawky, politic, prudent, regardful,
      safe, slow to act, tentative, thorough, uncommunicative, undaring,
      unenterprising, unprecipitate