Early 18th century; earliest use found in Robert South (1634–1716), Church of England clergyman and theologian. From opinionate + -er, perhaps as alteration of opinionator.
Definition of opinionater in US English:
opinionater
nounəˈpɪnjəneɪtə
rare
= opinionator.
Origin
Early 18th century; earliest use found in Robert South (1634–1716), Church of England clergyman and theologian. From opinionate + -er, perhaps as alteration of opinionator.