Negligent

wiktionary

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From Middle English necligent, negligent, from Old French negligent, from Latin negligēns.

etymonline

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negligent (adj.)

late 14c., necligent, of persons, "remiss, indifferent to duty," from Old French negligent "careless, negligent" (13c.) and directly from Latin negligentem (nominative neglegens) "heedless, careless, unconcerned," present participle of neglegere "to neglect" (see neglect (v.)). Of action, conduct, etc., c. 1500. Related: Negligently.