[noun] uncertainty about the truth or factuality of existence of something; "the dubiousness of his claim"; "there is no question about the validity of the enterprise" Synonyms:dubiousness, fulness, question
[verb] consider unlikely or have doubts about; "I doubt that she will accept his proposal of marriage"
[verb] lack confidence in or have doubts about; "I doubt these reports"; "I suspect her true motives"; "she distrusts her stepmother"