The Collaborative International Dictionary of English v.0.48:

Exacuate \Ex*ac"u*ate\, v. t. [L. exacure; ex out (intens.) +
   acuere to make sharp.]
   To whet or sharpen. [Obs.] --B. Jonson. -- Ex*ac`u*a"tion,
   n. [Obs.]
   [1913 Webster]