el diccionario inglés - inglés

to withdraw from an agreement or commitment inglés:

You could not back out from the project. The deal is a deal

Make them sign the agreement so that they would not back out from the project.

I hope they will not back out

It's too late to back out of the deal.

We went back out to my car and got in.

I'll sing, it's too late to back out.

After making the decision, you can't back out.