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1540s, from Latin perpetratus, past participle of perpetrare "to perform, to accomplish," from per- "completely" + patrare "carry out," originally "bring into existence," from pater "father" (see father (n.)). Earlier in English was perpetren, mid-15c., from Old French perpetrer. Neither good nor bad in Latin, first used in English in statutes, hence its sense of "to perform criminally." Related: Perpetrated; perpetrating.
literally "the one who did it" (in English usually an evil act), 1560s, from Late Latin perpetrator, agent noun of perpetrare "to perform, to accomplish" (see perpetrate). Fem. forms are perpetratress (1811, of Nero's poisoner Locusta); perpetratrix (1862, in reference to Charlotte Corday).