The Collaborative International Dictionary of English v.0.48:

Usurarious \U`su*ra"ri*ous\, Usurary \U"su*ra*ry\, a. [L.
   usurarius that serves for use, that pays interest. See
   Usurer.]
   Usurious. [Obs.] "Usurarious contracts." --Jer. Taylor. Bp.
   Hall.
   [1913 Webster]