A "coldwater flat" typically refers to a type of apartment or dwelling that lacks a central heating system and running hot water. This term, although specific in its meaning, can be substituted with various synonyms to convey the same concept. "Chilly apartment" aptly describes an abode that lacks warmth and comfortable amenities. "Unheated dwelling" is a straightforward replacement that emphasizes the absence of essential heating facilities. Additionally, "frigid flat" highlights the coldness in the living space, whereas "unwarmed apartment" underlines the absence of cozy temperatures. All of these synonyms effectively convey the idea of a coldwater flat, emphasizing the uncomfortable living conditions often associated with such dwellings.