Synonyms: incommutable
Definition: not subject to alteration or change
Similar words: inconvertible, untransmutable
Definition: not capable of being changed into something else
Usage: the alchemists were unable to accept the inconvertible nature of elemental metals
Similar words: unalterable
Definition: of a sentence; that cannot be changed
Usage: an unalterable death sentence
Synonyms: incommutable
Definition: not interchangeable or able to substitute one for another
Usage: a rare incommutable skill
Similar words: unexchangeable
Definition: not suitable to be exchanged