Degeneration

The act or state of growing worse, or the state of having become worse; decline; degradation; debasement; degeneracy; deterioration.

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; as, fatty degeneration of the liver.

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

The thing degenerated.

the process of declining from a higher to a lower level of effective power or vitality or essential quality