Lewis & Short

effĭcĭentĭa, ae, f. [efficio], efficient power, efficiency, influence (rare; mostly in philos. lang.), Cic. N. D. 2, 37, 95; id. Fat. 9, 19: spiritalis, Hil. in Psa. 131, 24: inenarrabilis, id. Trin. 3, 18; Lact. Opif. D. 19, 7.