game has 19 distinct synonyms spread across 5 of its 14 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 contest with rules to determine a winner
“you need four people to play this game”
a single play of a sport or other contest
“the game lasted two hours”
an amusement or pastime
“they played word games”
(tennis) a division of play during which one player serves
(games) the score at a particular point or the score needed to win
“the game is 6 all”
a secret scheme to do something (especially something underhand or illegal)
“they concocted a plot to discredit the governor”
the game equipment needed in order to play a particular game
“the child received several games for his birthday”
frivolous or trifling behavior
“for actors, memorizing lines is no game”
Synonyms, antonyms and the broader and narrower relations for game come from Princeton University’s WordNet. Full sources and licences.