Morbidity is any physical or psychological state considered to be outside the realm of normal well-being. The term morbidity is often used to describe illness, impairment, or degradation of health, especially when discussing chronic and age-related diseases which can worsen over time.
The expression "compression of morbidity" is the goal of medical and lifestyle interventions aimed at preserving health and wellness for as long as possible, before mortality (death) occurs.
Morbidity. International Union of Pure and Applied Chemistry (IUPAC) Glossary of Terms used in Toxicology. US Department of Health and Human Services Public Information Sheet. Accessed February 22, 2013.