Set concrete is a term used to describe concrete that has hardened and become firm. Some antonyms for set concrete include malleable, pliable, adaptable, and flexible. These words refer to materials that can be easily shaped or adjusted to fit specific needs or purposes. Unlike set concrete, which is often used for permanent structures or foundations, these materials can be modified or manipulated to meet changing requirements or circumstances. Other antonyms for set concrete include unfinished, fluid, and malleable. These words suggest that something is still in a state of flux, and that it can be shaped, altered, or adjusted as needed to achieve a desired outcome.