English to English

noun (n)

• (figurative) something regarded as sacred or inviolable(noun.attribute)

  Example:
  Every politician fears to touch that holy of holies, the Social Security System.
  

  source: wordnet30
• (Judaism) sanctuary comprised of the innermost chamber of the Tabernacle in the temple of Solomon where the Ark of the Covenant was kept(noun.artifact)

  Synonym:
  sanctum sanctorum
  

  source: wordnet30