Are you considered a backbiter if you sit in a place where backbiting occurs, and you are able to leave it, while detesting backbiting in your heart?

It is not permissible to listen to backbiting, as it is an affirmation of it. Rather, it is obligatory to denounce those who backbite and to clarify the impermissibility of backbiting. If denouncing is not possible or not effective, then the listener must leave the gathering of backbiting if he is able. If he sits and listens while he is able to leave, he sins by listening, even if he disapproves in his heart.