資料來源 : Webster's Revised Unabridged Dictionary (1913)

Indubious \In*du"bi*ous\, a. [L. indubius. See {In-} not, and
   {Dubious}.]
   1. Not dubious or doubtful; certain.

   2. Not doubting; unsuspecting. ``Indubious confidence.''
      --Harvey.