talk has 19 distinct synonyms spread across 9 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. Its one recorded opposite is keep quiet.
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.
divulge confidential information or secrets
“Be careful--his secretary talks”
an exchange of ideas via conversation
“let's have more work and less talk around here”
Synonyms, antonyms and the broader and narrower relations for talk come from Princeton University’s WordNet. Full sources and licences.
discussion; (`talk about' is a less formal alternative for `discussion of')
“his poetry contains much talk about love and anger”
the act of giving a talk to an audience
“I attended an interesting talk on local history”
a speech that is open to the public
“he attended a lecture on telecommunications”
idle gossip or rumor
“there has been talk about you lately”