To support with money, influence, or encouragement: as to “back a friend.” A commercial term meaning to endorse. When a merchant backs or endorses a bill, he guarantees its value.
“You care not who sees your back. Call you
that backing of your friends? A plague upon such backing!”—Shakespeare: 1 Henry IV., ii. 4.
“Englishmen will fight now as well as ever they did; and there is ample power to back them.”—W. Robertson: John Bright, chap. xxxi. p. 298.