Fig. to end one's association with someone or something. (Fig. on the notion of getting rid of a problem by removing it as if it were dirt on the hands.) I washed my hands of Tom. I wanted no more to do with him. That car was a real headache. I washed my hands of it long ago.
to end all involvement with someone or something Phil seemed cold and distant, and now she was very afraid that he would wash his hands of her.You can't just wash your hands of the problem of homelessness.
to stop being involved with or responsible for someone or something, usually because they have caused too many problems for you I should imagine he couldn't wait to wash his hands of the whole project.