The Collaborative International Dictionary of English v.0.48:

Arreptitious \Ar`rep*ti"tious\, a. [L. arreptitius.]
   Snatched away; seized or possessed, as a demoniac; raving;
   mad; crack-brained. [Obs.]
   [1913 Webster]

         Odd, arreptitious, frantic extravagances. --Howell.
   [1913 Webster]