Late 16th century; earliest use found in Henoch Clapham (fl. 1585–1614), writer on theology and preacher. From post-classical Latin plerophoria assurance, certainty and its etymon Hellenistic Greek πληροϕορία fullness of assurance, certainty (New Testament: Hebrews 6:11, 10:22, etc.) from πληροϕορεῖν to bring full measure, to satisfy fully (from πληρο-, combining form of ancient Greek πλήρης full, satisfied + ancient Greek ϕορείν to bear constantly: see -phoresis) + -ία.