sac ‧ ro ‧ sanct /ˈsækrəʊsæŋkt $ -roʊ-/ BrE AmE adjective
[ Date: 1600-1700 ; Language: Latin ; Origin: sacrosanctus , probably from sacro sanctus 'made holy by religious ceremonies' ]
something that is sacrosanct is considered to be so important that no one is allowed to criticize or change it SYN sacred :
Weekends are sacrosanct in our family.