The word 恶化 is formed by combining the character 恶, meaning "bad" or "evil", with the character 化, meaning "to change" or "to transform". Together, they create a concept where 化 acts as a verbal suffix, turning the state of "badness" described by 恶 into an active process. Thus, the compound literally signifies "to change for the worse" or "to deteriorate", capturing the idea of a negative transformation or decline in a single, efficient term.