Backslide and Fall away

Backslide verb - Drop to a lower level, as in one's morals or standards.

Fall away and backslide are semantically related In some cases you can use "Fall away" instead a verb "Backslide".

Fall away verb - To grow less in scope or intensity especially gradually.

Backslide and fall away are semantically related in return to earlier way of doing things topic. Sometimes you can use "Backslide" instead a verb "Fall away".