correspondent has 6 distinct synonyms spread across 3 of its 3 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.
someone who communicates by means of letters
a journalist employed to provide news stories for newspapers or broadcast media
similar or equivalent in some respects though otherwise dissimilar
“brains and computers are often considered analogous”
Synonyms, antonyms and the broader and narrower relations for correspondent come from Princeton University’s WordNet. Full sources and licences.