immutable
adjective /ɪˈmjuːtəbl/
  /ɪˈmjuːtəbl/
(formal)- that cannot be changed; that will never change synonym unchangeable- This decision should not be seen as immutable.
 Oxford Collocations DictionaryImmutable is used with these nouns:- truth
 Word Originlate Middle English: from Latin immutabilis, from in- ‘not’ + mutabilis, from mutare ‘to change’.