Emily Dickinson Lexicon

DU'BI-OUS, a. [L. dubius. See Doubt. The primary sense is probably to turn or to waver.]

1. Doubtful; wavering or fluctuating in opinion; not settled; not determined; as, the mind is in a dubious state.
2. Uncertain; that of which the truth is not ascertained or known; as, a dubious question.
3. Not clear; not plain; as, dubious light. – Milton.
4. Of uncertain event or issue. In dubious battle. – Milton.