sacrosanct
Concise Oxford English Dictionary © 2008 Oxford University Press:
sacrosanct /ˈsakrə(ʊ)saŋ(k)t, ˈseɪk-/
▶adjective regarded as too important or valuable to be interfered with.
– derivatives
sacrosanctity noun.
sacrosanctity noun.
– origin C15: from L. sacrosanctus, from sacro ‘by a sacred rite’ (ablative of sacrum) + sanctus ‘holy’.
'sacrosanct' also found in these Oxford entries:

