early 15c., repulsen, "hold (something) back; drive (someone) away," from Latin repulsus, past participle of repellere "drive back, reject" (see repel). Also compare Medieval Latin repulsare. Related: Repulsed; repulsing.
late 15c., "defeat," in part from the English verb, in part from Old French repulse, variant of repousse, and in part directly from Latin repulsa "refusal, denial" (as in repulsa petitio "a repulse in soliciting for an office"), noun use of fem. of repulsus, past participle of repellere "to drive back" (see repel).