Impair

v. t. [imp. & p. p. IMPAIRED; p. pr. & vb. n. IMPAIRING.] [Written also impair.] [O. Fr. empeirer, N. Fr. empirer, Lat. as if impejorare; prefix im, for in, and pejorare, to make worse; pejor, worse, Fr. pire, Pr. peire; Sp. empeorar, Pg. empeiorar, empeyorar. Cf. APPAIR.] To make worse; to diminish in quantity, value, excellence, or strength; to lessen in power; to weaken; to enfeeble; to deteriorate; as, to impair health, character, the mind, value, and the like. Time sensibly all things impairs. Roscommon. In years he seemed, but not impaired by years. Pope. Syn.—To diminish; decrease; injure; weaken; enfeeble.

To be lessened or worn out; to grow worse. [Obs.] Spenser.

a. [Fr. impair, It. impare, impari, Sp. & Lat. impar; Lat. im, for in, not, and par, equal.] Not fit or appropriate; unsuitable. [Obs.] “An impair thought.” Shak.

Diminution; decrease. [Obs.] Browne.