chaos has 4 distinct synonyms spread across 1 of its 4 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 state of extreme confusion and disorder
Synonyms, antonyms and the broader and narrower relations for chaos come from Princeton University’s WordNet. Full sources and licences.
the formless and disordered state of matter before the creation of the cosmos
(Greek mythology) the most ancient of gods; the personification of the infinity of space preceding creation of the universe
(physics) a dynamical system that is extremely sensitive to its initial conditions