sacred has 3 distinct synonyms spread across 2 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is profane.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
concerned with religion or religious purposes
“sacred texts”
made or declared or believed to be holy; devoted to a deity or some religious ceremony or use
“a consecrated church”
2 of the 5 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for sacred.
Synonyms, antonyms and the broader and narrower relations for sacred come from Princeton University’s WordNet. Full sources and licences.