The term "set figure" implies a fixed amount or quantity. However, there are several antonyms to this phrase that suggest an indefinite or variable amount. Words such as "fluid," "flexible," "changeable," "unsettled," and "inconsistent" are all appropriate antonyms for "set figure". Each of these words implies movement or fluctuation, which is the complete opposite of a fixed figure. A fluid figure suggests an amount that can easily change, while a flexible figure indicates an amount that can be adjusted as needed. An inconsistent figure signifies that the amount varies from time to time, while an unsettled figure implies that the amount is uncertain. Overall, these antonyms provide a broader picture of variability than the original phrase ever could.