ph.

1. 食言；违约；退出
If you back out, you decide not to do something that you previously agreed to do.

1. make a retreat from an earlier commitment or activity

e.g. We'll have to crawfish out from meeting with him
He backed out of his earlier promise
The aggressive investment company pulled in its horns

Synonym: retreatpull backback awaycrawfishcrawfish outpull in one's hornswithdraw

2. move out of a space backwards

e.g. He backed out of the driveway