| adjective | not subject or susceptible to change or variation in form or quality or nature “the view of that time was that all species were immutable, created by God” |
| adjective | unvarying in nature “maintained a constant temperature” |
| adjective | remaining the same for indefinitely long times |
| immutableness | noun | the quality of being incapable of mutation |
| immutability | noun | the quality of being incapable of mutation |
| changelessness | noun | the quality of being unchangeable; having a marked tendency to remain unchanged |
| constancy | noun | the quality of being enduring and free from change or variation |
| invariance | noun | the quality of being resistant to variation |
| unalterability | noun | the quality of being fixed and unchangeable |