Source : Webster's Revised Unabridged Dictionary (1913)

Fatuous \Fat"u*ous\, a. [L. fatuus.]
   1. Feeble in mind; weak; silly; stupid; foolish; fatuitous.
      --Glanvill.

   2. Without reality; illusory, like the ignis fatuus.

            Thence fatuous fires and meteors take their birth.
                                                  --Danham.

Source : WordNet®

fatuous
     adj : complacently or inanely foolish [syn: {asinine}, {inane}, {mindless},
            {vacuous}]