The Collaborative International Dictionary of English v.0.48:

Venturesome \Ven"ture*some\, a.
   Inclined to venture; not loth to run risk or danger;
   venturous; bold; daring; adventurous; as, a venturesome boy
   or act. -- Ven"ture*some*ly, adv. -- Ven"ture*some*ness,
   n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

venturesome
    adj 1: disposed to venture or take risks; "audacious visions of
           the total conquest of space"; "an audacious
           interpretation of two Jacobean dramas"; "the most daring
           of contemporary fiction writers"; "a venturesome
           investor"; "a venturous spirit" [syn: audacious,
           daring, venturesome, venturous]

Moby Thesaurus II by Grady Ward, 1.0:

51 Moby Thesaurus words for "venturesome":
   adventuresome, adventurous, aggressive, aleatory, ambitious,
   audacious, bold, brave, chancy, courageous, daredevil, daring,
   determined, dicey, doughty, driving, dynamic, enterprising,
   experimental, fearless, foolhardy, forceful, full of risk, game,
   go-ahead, hazardous, hustling, intrepid, overbold, plucky, pushful,
   pushing, pushy, rash, reckless, resolute, riskful, risky,
   speculative, spirited, sporting, stalwart, stout, sturdy,
   temerarious, tentative, trial, up-and-coming, venturous, wildcat,
   willing