The word "un-changeably" means something that cannot be altered or modified. Its antonyms, on the other hand, are words that describe the ability to change, transform or vary. These include words such as changeably, fickly, adjustable, pliable, adaptable, and flexible. For instance, if something is changeable, it means it can be modified easily or influenced by external factors, whereas if it's un-changeable, it's rigid and fixed in a certain form. In summary, having a range of antonyms to "un-changeably" means that there are always options available to transform, modify, or adjust something to suit any given situation.