car has 10 distinct synonyms spread across 5 of its 5 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 motor vehicle with four wheels; usually propelled by an internal combustion engine
“he needs a car to get to work”
a wheeled vehicle adapted to the rails of railroad
“three cars had jumped the rails”
the compartment that is suspended from an airship and that carries personnel and the cargo and the power plant
where passengers ride up and down
“the car was on the top floor”
a conveyance for passengers or freight on a cable railway
“they took a cable car to the top of the mountain”
Synonyms, antonyms and the broader and narrower relations for car come from Princeton University’s WordNet. Full sources and licences.