backslider

noun backslider

• recidivist — repeated or habitual relapse, as into crime.
• defaulter — A defaulter is someone who does not do something that they are legally supposed to do, such as make a payment at a particular time, or appear in a court of law.
• transgressor — to violate a law, command, moral code, etc.; offend; sin.
• apostate — An apostate is someone who has abandoned their religious faith, political loyalties, or principles.
• deserter — A deserter is someone who leaves their job in the armed forces without permission.