carrier has 13 distinct synonyms spread across 7 of its 11 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 self-propelled wheeled vehicle designed specifically to carry something
“refrigerated carriers have revolutionized the grocery business”
a large warship that carries planes and has a long flat deck for takeoffs and landings
an inactive substance that is a vehicle for a radioactive tracer of the same substance and that assists in its recovery after some chemical reaction
a person or firm in the business of transporting people or goods or messages
a radio wave that can be modulated in order to transmit a signal
a man who delivers the mail
(medicine) a person (or animal) who has some pathogen to which he is immune but who can pass it on to others
a rack attached to a vehicle; for carrying luggage or skis or the like
(genetics) an organism that possesses a recessive gene whose effect is masked by a dominant allele; the associated trait is not apparent but can be passed on to offspring
Synonyms, antonyms and the broader and narrower relations for carrier come from Princeton University’s WordNet. Full sources and licences.