doubtful(subject to, or causing doubt) adjective [UK: ˈdaʊt.fʊl] [US: ˈdaʊt.fəl]John was somewhat doubtful. = John estaba algo dudoso.
dubious(arousing doubt) adjective [UK: ˈdjuː.bɪəs] [US: ˈduː.biəs]Mary is a woman of dubious virtue. = Mary es una mujer de dudosa virtud.
questionable(of dubious respectability or morality) adjective [UK: ˈkwes.tʃə.nəb.l̩] [US: ˈkwes.tʃə.nəb.l̩]She is a tender girl of questionable morals. = Ella es una tierna chica de dudosa moral.
