The term 'faith abandoner' is a synonym for APOSTATE, which is an 8-letter word. An APOSTATE is someone who has abandoned their religious faith or beliefs, either by choice or due to external pressures. This could be a person who was raised in a certain faith but has since renounced it, or someone who was never religious but has since adopted a different faith. Apostasy is a controversial topic in many religions, and can be seen as a form of betrayal.