harmonious ...a1670 obs. rare
adaptation of Old French concordieux, -euse, adaptation of medieval Latin concordiōs-us, formed on. concordia: + -ous.
FIRST DOCUMENTED USE
a1670 - see EXAMPLE below
"...the King found himself at more Leisure and Freedom, in the Absence of the Lord Marquess, to study the Calling of a Comfortable and Concordious Parliament, wherein the Subject might reap Justice, and the Crown Honour..."
From: Scrinia Reserata: A Memorial Offer'd to the Great Deservings of John Williams, D.D. Who some time held the Places of Ld Keeper of the Great Seal of England, Ld Bishop of Lincoln, and Ld Archbishop of York. Containing a Series of the Most Remarkable Occurrences and Transactions of his Life, in Relation both to Church and State
- John Hacket, 1693