degeneration

noun

1. (countable, uncountable, usually)The process or state of growing worse, or the state of having become worse.

   “The modern cry of "more liberty and less creed" is a degeneration from a vertebrate to a jellyfish.”

   “Hence, regional soil degenerations and podsolization was probably an important factor contributing to the retrogressive change in the forest composition at the end of the mesocratic phase..”

   “Emmanuel Macron sounded like a man in grief. Not angry, not defiant, just a little triste. Europe, he lamented, was suffering a “degeneration of democracy”.”

2. (uncountable, usually)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. (uncountable, usually)Gradual deterioration, from natural causes, of any class of animals or plants or any particular organ or organs; hereditary degradation of type.
4. (countable, usually)A thing that has degenerated.

   “cockle, aracus, […] and other degenerations”