The Collaborative International Dictionary of English v.0.48:

Improperation \Im*prop`er*a"tion\, n. [L. improperare,
   improperatum, to taunt.]
   The act of upbraiding or taunting; a reproach; a taunt.
   [Obs.]
   [1913 Webster]

         Improperatios and terms of scurrility.   --Sir T.
                                                  Browne
   [1913 Webster]