Something, especially rules and customs, that cannot be changed at all is said to be etched in stone.
etched in stone
Permanently anchored or durably established; not accountable to any about-face or alteration. Often acclimated in the negative. The accord isn't yet categorical in stone, but we're assured it will go advanced as hoped.Learn more: etch, stoneLearn more:
An Etched in stone idiom dictionary is a great resource for writers, students, and anyone looking to expand their vocabulary. It contains a list of words with similar meanings with Etched in stone, allowing users to choose the best word for their specific context.
Dizionario di parole simili, diverso tenore, sinonimi, di invocazione per Idioma Etched in stone