Source : Webster's Revised Unabridged Dictionary (1913)

Evacuant \E*vac"u*ant\, a. [L. evacuans, -antis, p. pr. of
   evacuare: cf. F. ['e]vacuant.]
   Emptying; evacuative; purgative; cathartic. -- n. (Med.) A
   purgative or cathartic.

Source : WordNet®

evacuant
     adj : strongly laxative [syn: {cathartic}, {purgative}]