The opposite of the phrase "most improv" can be any particular word that means the opposite of improvement, such as worsen, decline or deteriorate. These words suggest a negative progress or development, a lessening of quality, or a decrease in value. For example, if a certain situation is "most improved" from its previous state, then it's opposite would be "most worsened" or "most declined" from the previous condition. In summary, the antonyms for "most improv" are any word or phrase that signifies degeneration, regression or backwardness, implying a lack of growth and progress.