Făt'ū-oŭs, a.

a. [Lat. fatuus, It., Sp., & Pg. fatuo, Pr. & Fr. fat.]

1. Feeble in mind; weak; silly; stupid; foolish; fatuitous. Glanville.
2. Impotent; without reality; illusory, like the ignis fatuus.

Thence fatuous fires and meteors take their birth. Denham.