buy has 6 distinct synonyms spread across 3 of its 6 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. Its one recorded opposite is sell.
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.
Synonyms, antonyms and the broader and narrower relations for buy come from Princeton University’s WordNet. Full sources and licences.
be worth or be capable of buying
“This sum will buy you a ride on the train”
acquire by trade or sacrifice or exchange
“She wanted to buy his love with her dedication to him and his work”
accept as true
“I can't buy this story”
an advantageous purchase
“she got a bargain at the auction”