fall away

verb4

1. •
   To slope downward.
2. •
   To cease to support a person or cause.

   • After the divorce, all his friends fell away one by one.
3. •
   To diminish in size, weight, or intensity.

   • One colour falls away by just degrees, and another rises insensibly. — 1697
4. •
   To perish; to vanish; to be lost.

   • How […] can the soul […] fall away into nothing? — 1711