Defender

wiktionary

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From Middle English defender, deffender, defendere, defendour, defendoure, partly from Anglo-Norman defendour, from Old French defendëor; partly from Middle English defenden + -ere, equivalent to defend +‎ -er.

etymonline

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defender (n.)

c. 1300, defendour, "one who protects from injury a champion" (early 13c. as a surname), via Anglo-French from Old French defendeor, agent noun from defendre (see defend). The Latin word in this sense was defensor.