degeneration

noun

1. 1

   The process or state of growing worse, or the state of having become worse.

2. 2

   That condition of a tissue or an organ in which its vitality has become either diminished or perverted; a substitution of a lower for a higher form of structure.

   “fatty degeneration of the liver”

3. 3

   Gradual deterioration, from natural causes, of any class of animals or plants or any particular organ or organs; hereditary degradation of type.

4. 4

   A thing that has degenerated.