assimilation has 2 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. 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.
the state of being assimilated; people of different backgrounds come to see themselves as part of a larger national family
the social process of absorbing one cultural group into harmony with another
Synonyms, antonyms and the broader and narrower relations for assimilation come from Princeton University’s WordNet. Full sources and licences.
the process of absorbing nutrients into the body after digestion
a linguistic process by which a sound becomes similar to an adjacent sound
the process of assimilating new ideas into an existing cognitive structure
in the theories of Jean Piaget: the application of a general schema to a particular instance