[in.com.mut.able] adj [ME, fr. L incommutabilis, fr. in- + commutabilis commutable] (15c): not commutable: as a: not interchangeable b: unchangeable -- in.com.mut.ably adv
INCOMMUTABLE
Meaning of INCOMMUTABLE in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012