Most unfixed refers to something that is not very set in stone, volatile or changeable. The antonyms for this term would be words such as definite, settled, stable, reliable, firm, secure, constant or fixed. Those words suggest that something is unwavering, dependable, and rigid. The antonyms of most unfixed present the opposite meaning, an idea of something that is sure, certain, and trustworthy. When we use antonyms, we can give readers a more comprehensive understanding of what we mean so they can differentiate between the two words and understand the context of the content.