The simple statement, unbacked by any proof but the weight of Ralph's new authority, brought light and happiness.
William Golding, Lord of the Flies(1954)
A mere remonstrance with him on the treatment of your colleagues, unbacked by force, would be futile.
Strang, Herbert, Swift and Sure(2012)
Unbacked, un-bakt′, adj. never yet ridden: without any to help or encourage: not supported by bets, of a racehorse, &c.
Various, Chambers's Twentieth Century Dictio...(2012)