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inefficacy


in·ef·fi·ca·cy

noun \(ˌ)i-ˈne-fi-kə-sē\

Definition of INEFFICACY

: lack of power to produce a desired effect

Origin of INEFFICACY

Late Latin inefficacia, from Latin inefficac-, inefficax inefficacious, from in- + efficac-, efficax efficacious
First Known Use: circa 1615

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