immutable
adjective formal uk/ɪˈmjuː.tə.bəl/ us/ɪˈmjuː.t̬ə.bəl/
永恒的;不可改变的
not changing, or unable to be changed
an immutable law 永恒的法则
Some people regard grammar as an immutable set of rules. 有些人认为语法是一套不可更改的规则。
Synonym: changeless
Opposites: changeablemutable