backslide

to draw back or apostatize in matters of religion (Acts 21:21; 2 Thess. 2:3; 1 Timothy 4:1)

This may be either partial (Proverbs 14:14) or complete (Hebrews 6:4-6; 10:38-39). The apostasy may be both doctrinal and moral.

Author: Matthew G. Easton.