The Collaborative International Dictionary of English v.0.48:

Fastuous \Fas"tu*ous\, a. [L. fastuosus, from fastus
   haughtiness, pride: cf. F. fastueux.]
   Proud; haughty; disdainful. [Obs.] --Barrow. --
   Fas"tu*ous*ness, n. [Obs.] --Jer. Taylor.
   [1913 Webster]