Falling to bits is a phrase used to describe something that is in a state of disrepair or close to falling apart. There are several synonyms that can be used to describe this condition. One of the most common is "crumbling", which implies that the object or structure is breaking down into smaller pieces. Another synonym is "deteriorating", which suggests a gradual decline in quality or condition. Other options include "decaying", "eroding", "disintegrating", and "collapsing". No matter which synonym is used, all convey the same message of something that is breaking down and in need of repair or replacement.