adjective/i.mɥabl/
Which hardly ever changes; unchanging; Incapable, by its very nature, of changing; immutable, fixed; Said of someone that remains true to themselves
“2008, 2Mimouche, "Bafouille à Sarko (en réponse au précédent post)", Un collège de France, February 20, 2008, Belle leçon de remise en cause des principes des lumières et de retour à un ordre établi immuable.” — (please add an English translation of this quotation)
After Latin immutābilis (compare immutable) with influence of Old French muable (“subject to change”).