card has 23 distinct synonyms spread across 9 of its 13 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.
one of a set of small pieces of stiff paper marked in various ways and used for playing games or for telling fortunes
“he collected cards and traded them with the other boys”
a card certifying the identity of the bearer
“he had to show his card to get in”
a rectangular piece of stiff paper used to send messages (may have printed greetings or pictures)
“they sent us a card from Miami”
a printed or written greeting that is left to indicate that you have visited
a list of dishes available at a restaurant
“the menu was in French”
(baseball) a list of batters in the order in which they will bat
“the managers presented their cards to the umpire at home plate”
a printed circuit that can be inserted into expansion slots in a computer to increase the computer's capabilities
ask someone for identification to determine whether he or she is old enough to consume liquor
“I was carded when I tried to buy a beer!”
Synonyms, antonyms and the broader and narrower relations for card come from Princeton University’s WordNet. Full sources and licences.