bearer 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.
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 messenger who bears or presents
“a bearer of good tidings”
Synonyms, antonyms and the broader and narrower relations for bearer come from Princeton University’s WordNet. Full sources and licences.
the person who is in possession of a check or note or bond or document of title that is endorsed to him or to whoever holds it
“the bond was marked `payable to bearer'”