Antonyms for the phrase "making improvement" include "decline," "deterioration," and "regression." These words all express a negative trend rather than progress. Additionally, "stagnation," "plateau," and "no change" can suggest a lack of advancement. Other antonyms can be connected to specific instances; for example, "worsening" suggests a declined condition, "retrogression" indicates a step backward, and "weakening" can suggest a decrease in power or capability. When considering antonyms for "making improvement," it's necessary to note that progress is not always guaranteed, and in some circumstances, setbacks may occur.