back against the wall{adv. phr.} In a trap, with no way to escape; in bad trouble.
The soldiers had their backs to the wall. He was in debt and could not get any help; his back was against the wall. The team had their backs to the wall in the second half. Compare: BETWEEN THE DEVIL AND THE DEEP BLUE SEA, LAST DITCH, ON THE SPOT, UP AGAINST IT.
[TahlilGaran] English Idioms Dictionary ▲