1920s; earliest use found in Arthur Cecil Pigou (1877–1959), economist. From French ophélimité from ancient Greek ὠϕέλιμος useful, serviceable (from the same base as ὄϕελος advantage, help, ὀϕέλλειν to increase, enlarge, strengthen, of uncertain origin + -ιμος, extended form of -μος, suffix forming nouns) + French -ité.