questionable, not certain

संदेहास्पद

English Usage: His alibi was doubtful given the circumstances.

Hindi Usage: उसकी कोई बहाना संदेहास्पद थाgiven the circumstances.

the state of being uncertain or having doubts

संदेहपूर्णता

English Usage: Her doubtfulness made it difficult to make a decision.

Hindi Usage: उसकी संदेहपूर्णता ने निर्णय लेने में मुश्किल पैदा की।

to feel uncertain about something

संदेह करना

English Usage: I doubt that he will arrive on time.

Hindi Usage: मुझे संदेह है कि वह समय पर पहुंचेगा।