"Un-fixed" is a term which signifies something that is not stable, immutable or unchanging, and lacks a definite form. Its antonyms include words such as "permanent," "immutable," "fixed," "established," and "settled." These words signify something that has a lasting relevance, definitive form, or a generalized understanding. Furthermore, the antonym of "un-fixed" can imply qualities of reliability, constancy, and longevity. For instance, a permanent structure like a building is considered to be reliable, constant and permanent. Similarly, an immutable law or principle transcends time and is universally applicable. Antonyms of "un-fixed" provide a sense of stability, permanence, and continuity, and therefore, constitute an essential part of language usage.