degeneration

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..

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

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

A thing that has degenerated.

cockle, aracus, […] and other degenerations