Difference between Doubtful and DubiousDoubtful is generally used to imply uncertainty about facts, whereas dubious implies suspicion about the value or genuineness. Both can be used for people, though their usage generally differs. For example: We are a little doubtful about the statements that have to be extracted from the witnesses in this case. For example: The right to know the human cost of the war was overruled on the dubious grounds that the information could help the enemy.