sac ‧ ri ‧ lege /ˈsækrəlɪdʒ, ˈsækrɪlɪdʒ/ BrE AmE noun [uncountable and countable]
[ Date: 1300-1400 ; Language: Old French ; Origin: Latin sacrilegium , from sacer ( ⇨ ↑ sacred ) + legere 'to gather, steal' ]
1 . when someone treats something holy in a way that does not show respect
2 . when someone treats something that another person thinks is very important or special without enough care or respect
it is sacrilege (for somebody) to do something
It’s sacrilege to even think of destroying that lovely building.
—sacrilegious /ˌsækrəˈlɪdʒəs◂, ˌsækrɪˈlɪdʒəs◂/ adjective