dubitable

from WordNet (r) 3.0 (2006)

dubitable
    adj 1: open to doubt or suspicion; "the candidate's doubtful
           past"; "he has a dubious record indeed"; "what one found
           uncertain the other found dubious or downright false";
           "it was more than dubitable whether the friend was as
           influential as she thought"- Karen Horney [syn:
           {doubtful}, {dubious}, {dubitable}, {in question(p)}]

from The Collaborative International Dictionary of English v.0.48

Dubitable \Du"bi*ta*ble\, a. [L. dubitabilis. Cf. {Doubtable}.]
   Liable to be doubted; uncertain. [R.] --Dr. H. More. --
   {Du"bi*ta*bly}, adv. [R.]
   [1913 Webster]