The Collaborative International Dictionary of English v.0.48:

Absterge \Ab*sterge\, v. t. [L. abstergere, abstersum; ab, abs +
   tergere to wipe. Cf. F absterger.]
   To make clean by wiping; to wipe away; to cleanse; hence, to
   purge. [R.] --Quincy.
   [1913 Webster]