Doubtful
Part of speech: adjective
Definition: Subject to, or causing doubt Experiencing or showing doubt Undecided or of uncertain outcome Improbable or unlikely Suspicious, or of dubious character
Example sentence: In necessary things, unity; in doubtful things, liberty; in all things, charity.
Dubious
Part of speech: adjective
Definition: Arousing doubt; questionable; open to suspicion.In disbelief; wavering, uncertain, or hesitating in opinion; inclined to doubt; undecided.
Example sentence: The Latin American debt that reached crisis levels from 1982 would have been sharply reduced by return of flight capital - in some cases, overcome, though all figures are dubious for these secret and often illegal operations.