syndicate has 5 distinct synonyms spread across 2 of its 6 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.
a loose affiliation of gangsters in charge of organized criminal activities
an association of companies for some definite purpose
Synonyms, antonyms and the broader and narrower relations for syndicate come from Princeton University’s WordNet. Full sources and licences.
a news agency that sells features or articles or photographs etc. to newspapers for simultaneous publication