early 15c. (Chauliac), "reduce swelling by repelling the humor causing it," from Latin repercusus, past participle of repercutere "to strike or beat back" (see repercussion). General sense of "beat or drive back" is from c. 1500. Related: Repercussed; repercussing.

late 14c., repercussif, "having the power to drive back" (originally in medicine, in reference to excessive concentrations of a humor), from Old French repercussif and directly from Medieval Latin repercussivus, from Latin repercuss-, past-participle stem of repercutere "to strike or beat back" (see repercussion). Related: Repercussively; repercussiveness.