pontifical has 8 distinct synonyms spread across 3 of its 4 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. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
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.
proceeding from or ordered by or subject to a pope or the papacy regarded as the successor of the Apostles
“papal dispensation”
denoting or governed by or relating to a bishop or bishops
puffed up with vanity
“a grandiloquent and boastful manner”
the vestments and other insignia of a pontiff (especially a bishop)
Synonyms, antonyms and the broader and narrower relations for pontifical come from Princeton University’s WordNet. Full sources and licences.