The Collaborative International Dictionary of English v.0.48:

Robustious \Ro*bus"tious\, a. [Cf. L. robusteus of oak.]
   Robust. [Obs. or Humorous] --W. Irving.
   [1913 Webster]

         In Scotland they had handled the bishops in a more
         robustious manner.                       --Milton.
   [1913 Webster] -- Ro*bus"tious*ly, adv. --
   Ro*bus"tious*ness, n.
   [1913 Webster]