What is "incommutable"

Incommutable \In`com*mut"a*ble\, a. [L. incommutabilis: cf. F. incommutable. See In- not, and Commutable.] Not commutable; not capable of being exchanged with, or substituted for, another.
--Cudworth. -- In`com*mut"a*ble*ness, n. -- In`com*mut"a*bly, adv.

a. Not commutable

1. adj. not subject to alteration or change [ant: commutable]

2. not interchangeable or able to substitute one for another; "a rare incommutable skill"