1. 
[syn: doubtful, dubious, dubitable, in question(p)]
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]
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)]