Emily Dickinson Lexicon

DOUBT, v.i. [dout; Fr. douter; L. dubito; It. dubitare; Sp. dudar; Arm. doueti. According to Ainsworth, this is composed of duo and bito, to go. It is evidently from the root of dubius, and of two; but the manner of formation is not clear. So D. twyffelen, to doubt, G. zweifeln, Sw. tvifla, D. tvivler, are from two.]

1. To waver or fluctuate in opinion; to hesitate; to be in suspense; to be in uncertainty, respecting the truth or fact; to be undetermined. Even in matters divine, concerning some things, we may lawfully doubt and suspend our judgment. – Hooker. So we say, I doubt whether it is proper; I doubt whether I shall go; sometimes with of, as we doubt of a fact.
2. To fear; to be apprehensive; to suspect. I doubt there's deep resentment in his mind. – Otway.