Unaffected by a specified operation (especially by a transformation)
Neither covariant nor contravariant.
not varying; constant
An invariant quantity, function etc.
Incapable of being reversed, recalled, repealed, or annulled.
Incapable of being reversed or turned about or back; incapable of being made to run backward.
Incapable of being reversed to the original state without consumption of free energy and increase of entropy.