sensationalism has 4 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.
subject matter that is calculated to excite and please vulgar tastes
the journalistic use of subject matter that appeals to vulgar tastes
“the tabloids relied on sensationalism to maintain their circulation”
Synonyms, antonyms and the broader and narrower relations for sensationalism come from Princeton University’s WordNet. Full sources and licences.
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.
(philosophy) the ethical doctrine that feeling is the only criterion for what is good
(philosophy) the doctrine that knowledge derives from experience