The antonyms for the word "in-alterable" are alterable, changeable, modifiable, mutable, and adjustable. Alterable refers to the property of being capable of being altered, changed or modified. Changeable denotes that something can be altered or replaced easily. Modifiable pertains to the quality of being open to modification or adaptation. Mutable implies that something is susceptible to change or variation, especially due to external factors. Adjustable is a term used in the context of modification to bring something to a desired state. These antonyms signify the opposite of in-alterable which means something that cannot be changed or altered in any way.