The Collaborative International Dictionary of English v.0.48:

Ventriloquous \Ven*tril"o*quous\, a. [L. ventriloquus a
   ventriloquist; venter the belly + loqui, p. p. locutus, to
   speak. See Ventral, and Loquacious.]
   Of or pertaining to a ventriloquist or ventriloquism.
   [1913 Webster]