1. 放弃；退出
If you back away from a commitment that you made or something that you were involved with in the past, you try to show that you are no longer committed to it or involved with it.

2. （常因害怕等而）后退，退缩
If you back away, you walk backwards away from someone or something, often because you are frightened of them.

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 outcrawfishcrawfish outpull in one's hornswithdraw