I'll describe backsliders as those that turn from God or to turn from Heaven .. It also means stubbornness and rebelliousness. For those who were rescued or born again go into impiety from Christ, they are rebellious. Backsliding is about someone who knows God in reality, not just a goer in the church.
Someone who has known the difference between sin and justice and who existed right before, is now restoring the evil he once repented. Some of them are also not backward but bent around.
"If they have escaped the corruption of the world by knowing our Lord and Savior Jesus Christ and are again entangled in it and are overcome, they are worse off at the end than they were at the beginning. It would have been better for them not to have known the way of righteousness, than to have known it and then to turn their backs on the sacred command that was passed on to them. Of them the proverbs are true: “A dog returns to its vomit,” and, “A sow that is washed returns to her wallowing in the mud.”_ - 2 Peter 2:20-22.