Hi angliholic,
There are a few alternative ways to say "back off":
back down = reverse one's upward course, descend, as in
When she saw the asps' nest on the top of the roof, she hastily backed down the ladder.
chicken out = back out from fear, loose one's nerve, as in
In the end I chickened out and look the easier rote down the mountain.
pull out = leave, depart, as in
The bus puled out at noon.
withdraw from an undertaking, as in
After the crash many investors pulled out of the market.
bow out = depart, withdraw, resign, as in
After five years as chairman, I felt it was time I bowed out.
Regards.
V.
