| Noun | 1. | mutableness - the quality of being capable of mutation changeability, changeableness - the quality of being changeable; having a marked tendency to change; "the changeableness of the weather" alterability - the quality of being alterable vicissitude - mutability in life or nature (especially successive alternation from one condition to another) immutability, immutableness, fixity - the quality of being incapable of mutation; "Darwin challenged the fixity of species" |