noun the thing degenerated.
2. degeneration ·noun the act or state of growing worse, or the state of having become worse; decline; degradation; debasement; degeneracy; deterioration.
3. degeneration ·noun a gradual deterioration, from natural causes, of any class of animals or plants or any particular organ or organs; hereditary degradation of type.
4. degeneration ·noun 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.