president of the united states has 3 distinct synonyms spread across 2 of its 2 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.
the person who holds the office of head of state of the United States government
“the President likes to jog every morning”
the office of the United States head of state
“a President is elected every four years”
Synonyms, antonyms and the broader and narrower relations for president of the united states come from Princeton University’s WordNet. Full sources and licences.