The Collaborative International Dictionary
Piacle
Piacle \Pi"a*cle\, n. [L. piaculum a propitiatory sacrifice,
that which requires expiation, a wicked action, fr. piare to
appease, to expiate, pius pious.]
A heinous offense which requires expiation. [R.]
--Howell.
Wiktionary
piacle
n. A heinous offense which requires expiation.