The Collaborative International Dictionary of English v.0.48:

Detersive \De*ter"sive\, a. [Cf. d['e]tersif.]
   Cleansing; detergent. -- n. A cleansing agent; a detergent.
   [1913 Webster]

WordNet (r) 3.0 (2006):

detersive
    adj 1: having cleansing power [syn: detergent, detersive]