- dubious about agreeing to go.
- he has a dubious record indeed.
- it was doubtful whether she would be admitted.
- it was more than dubitable whether the friend was as influential as she thought.
- the candidate's doubtful past.
- they admitted the force of my argument but remained dubious.
- they were doubtful that the cord would hold.
- what one found uncertain the other found dubious or downright false.