from Latin vāniloquentia idle talk, chatter, boastful speech
1727 - An Universal Etymological English Dictionary, Nathan Bailey;
"Vaniloquent, talking vainly"
From: The Retrospective Review:
Consisting of Criticisms Upon, Analyses Of, and Extracts from Curious, Valuable,
and Scarce Old Books
Volume I. 1853
Art. V. Early Scottish History and its Exponents, By Thomas Innes, 1729