incommutable

adjectives

not subject to alteration or change
antonym
is similar to
not capable of being changed into something else
"the alchemists were unable to accept the inconvertible nature of elemental metals"
is similar to
of a sentence; that cannot be changed
"an unalterable death sentence"
not interchangeable or able to substitute one for another
"a rare incommutable skill"
is derived from
is similar to
not suitable to be exchanged