truck has 2 distinct synonyms spread across 2 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.
an automotive vehicle suitable for hauling
a handcart that has a frame with two low wheels and a ledge at the bottom and handles at the top; used to move crates or other heavy objects
convey (goods etc.) by truck
“truck fresh vegetables across the mountains”
Synonyms, antonyms and the broader and narrower relations for truck come from Princeton University’s WordNet. Full sources and licences.