DOUBTFUL Copy link • DOUBTFULI. Subjective, of persons, dubius (when one does not know what to choose): incertus (when one does not know what conclusion to draw, or what resolution to take): to be doubtful, dubium esse; in dubio esse; dubitare; incertum esse; animo or animi pendere. I am doubtful what to do, dubius, or incertus, sum, quid faciam; incertum mihi est, or in incerto habeo, quid faciam; dubius, or incertus, sum, utrum - an; non satis mihi constat, ... ne (appended) ... an. II. Objective; that occasions doubt, dubius: incertus: anceps: ambiguus (dubius and ambiguus denote doubt with reference to success or failure; good or bad luck, etc.; anceps, with reference to the very existence of a thing; e.g., bellum dubia et interdum ancipiti fortuna gestum, Döderlein; ambiguus also refers to trustworthiness; e.g., homo ambigua fide; homo ambigui ingenii): doubtful cases, ea quae dubitationem afferunt: to be doubtful, incertum or dubium esse; non constare: to leave a thing doubtful, aliquid in medio, in dubio, in incerto relinquere: to become doubtful, in dubium venire.