Webster's 1828 Dictionary
BACKSLIDER
n.An apostate; one who falls from the faith and practice of religion. Proverbs 14:14. 2. One who neglects his vows of obedience and falls into sin.
Webster's 1913 Dictionary
BACKSLIDER
BACKSLIDER Back "slid "er, n.
Defn: One who backslides.
American Oxford Thesaurus
backslider
backslider noun I'll have no backslider like you in my family: recidivist, regressor; defector, deserter, turncoat, apostate, fallen angel.
Oxford Thesaurus
backslider
backslider noun recidivist, regressor; apostate, defector, deserter, turncoat, renegade, fallen angel.
The Wordsmith Dictionary