Origin: 1275–1325; Middle English < Latin ūsūrpāre to take possession through use, equivalent to ūsū (ablative of ūsususe (noun)) + -rp-, reduced form of -rip-, combining form of rapere to seize + -āre infinitive ending
early 14c., from O.Fr. usurper, from L. usurpare "make use of, seize for use," in L.L. "to assume unlawfully," from usus "a use" (see use) + rapere "to seize" (see rapid).