What are the opposite words for improvement?

Improvement is a term used to describe the act of making something better. However, in some cases, we also need to have a word that describes the opposite of improvement. The antonyms for improvement include deterioration, decline, regression, deterioration, worsening, and setback. Deterioration is a term that describes the state of something becoming progressively worse. It can be used in any context, from physical things such as a building to mental health. Decline is a synonym for deterioration, but it's often used to describe health, economic or cultural decline. Regression implies a return to an earlier state, such as regression in developmental psychology where people return to behavior patterns of an earlier developmental period. Lastly, worsening and setback describe the act of getting worse or hampering the progress of something.