Source : Webster's Revised Unabridged Dictionary (1913)

Piacular \Pi*ac"u*lar\, a. [L. piacularis: cf. F. piaculaire.]
   1. Expiatory; atoning. --Sir G. C. Lewis.

   2. Requiring expiation; criminal; atrociously bad. ``Piacular
      pollution.'' --De Quincey.