Open to question

The Collaborative International Dictionary Word definitions in The Collaborative International Dictionary
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.]

WordNet Word definitions in WordNet
adj. 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"- ...

Wiktionary Word definitions in Wiktionary
a. Capable of being doubted; susceptible of being questioned.