Early 19th century; earliest use found in The Critical Review. From post-classical Latin adaequativus from classical Latin adaequāt-, past participial stem of adaequāre + -īvus.
Definition of adequative in US English:
adequative
adjectiveˈadəkwətɪv
rare
Adequate, suitable.
Origin
Early 19th century; earliest use found in The Critical Review. From post-classical Latin adaequativus from classical Latin adaequāt-, past participial stem of adaequāre + -īvus.