There are several synonyms for the term "bad condition" that can be used to describe a state of decline or deterioration. For instance, "poor condition" is a widely-used synonym that denotes a state of disrepair, while "rough condition" refers to something that is in a deteriorated or damaged state. Similarly, "unsatisfactory condition" conveys the idea that something is below par or not up to standard. "Degenerated condition" is also another synonym that describes a state of decline or slipping away from its original state. Other potential synonyms might include "worn down," "dilapidated," or "decayed." Overall, using a synonym for "bad condition" can help to vary your writing and make it more engaging for readers.