association has 5 distinct synonyms spread across 2 of its 8 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 disassociation.
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 formal organization of people or groups of people
“he joined the Modern Language Association”
the act of consorting with or joining with others
“you cannot be convicted of criminal guilt by association”
the state of being connected together as in memory or imagination
“his association of his father with being beaten was too strong to break”
the process of bringing ideas or events together in memory or imagination
“conditioning is a form of learning by association”
a social or business relationship
“a valuable financial affiliation”
a relation resulting from interaction or dependence
“flints were found in association with the prehistoric remains of the bear”
(chemistry) any process of combination (especially in solution) that depends on relatively weak chemical bonding
(ecology) a group of organisms (plants and animals) that live together in a certain geographical region and constitute a community with a few dominant species
Synonyms, antonyms and the broader and narrower relations for association come from Princeton University’s WordNet. Full sources and licences.