Etymology
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impair (v.)
late 14c., a re-Latinizing of earlier ampayre, apeyre "make worse, cause to deteriorate" (c. 1300), from Old French empeirier "make worse" (Modern French empirer), from Vulgar Latin *impeiorare "make worse," from assimilated form of in- "into, in" (from PIE root *en "in") + Late Latin peiorare "make worse," from peior "worse," perhaps originally "stumbling," from PIE *ped-yos-, suffixed (comparative) of *ped- "to walk, stumble, impair," from root *ped- "foot. In reference to driving under the influence of alcohol, first recorded 1951 in Canadian English. Related: Impaired; impairing.
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unimpaired (adj.)
1580s, from un- (1) "not" + past participle of impair (v.). Rare before c. 1760.
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impairment (n.)
mid-14c., emparement, from Old French empeirement, from empeirier (see impair). Re-Latinized spelling is from 1610s.
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superannuate (v.)
1640s, "render obsolete," back-formation from superannuated. Meaning "impair or disqualify by old age" is from 1690s. Related: Superannuating.
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debase (v.)

1560s, "lower in position, rank, or dignity, impair morally," from de- "down" + base (adj.) "low," on analogy of abase (or, alternatively, from obsolete verb base "to abuse"). From 1590s as "lower in quality or value" (of currency, etc.), "degrade, adulterate." Related: Debased; debasing; debasement.

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debilitate (v.)

"weaken, impair the strength of, enfeeble, make inactive or languid," 1530s, from Latin debilitatus, past participle of debilitare "to weaken," from debilis "weak, helpless," from de "from, away" (see de-) + -bilis "strength," from PIE root *bel- "strong" (see Bolshevik). Related: Debilitated; debilitating.

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pejoration (n.)

"deterioration, a becoming worse," 1650s, noun of action from pejorate (1640s), from Late Latin peiorare "make worse," from Latin peior "worse," perhaps originally "stumbling," from PIE *ped-yos-, suffixed (comparative) form of *ped- "to walk, stumble, impair," from root *ped- "foot." Meaning "a lowering or deterioration of the sense of a word" is by 1889.

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enervate (v.)
c. 1600, "deprive of force or strength," from Latin enervatus, past participle of enervare "to weaken" (see enervation). Literal sense of "to weaken, impair" in English is from 1610s. Related: Ennervated; ennervating. As a verb Middle English had enerve (c. 1400, eneruyd).
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disfigure (v.)
Origin and meaning of disfigure

late 14c., "mar the external figure of, impair the beauty, symmetry, or excellence of," also "transform the appearance of, disguise," from Old French desfigurer "disfigure, alter, disguise, destroy," from Medieval Latin diffigurare, from assimilated form of Latin dis- (see dis-) + figurare "to form, shape," from figura "a shape, form, figure" (from PIE root *dheigh- "to form, build"). Related: Disfigured; disfiguring; disfiguration.

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pejorative (adj.)

"depreciative, disparaging, giving a low or bad sense to," 1888, from French péjoratif, from Late Latin peiorat-, past-participle stem of peiorare "make worse," from Latin peior "worse," perhaps originally "stumbling," from PIE *ped-yos-, suffixed (comparative) form of *ped- "to walk, stumble, impair," from root *ped- "foot." As a noun, "a word that depreciates the sense," from 1882. English had a verb pejorate "to worsen" from 1640s.

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