figure eight has 2 distinct synonyms spread across 2 of its 3 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 two-dimensionsal figure having the shape of the number eight
a knot having the shape of the numeral 8; tied in a rope that has been passed through a hole or pulley and that prevents the rope from coming loose
Synonyms, antonyms and the broader and narrower relations for figure eight come from Princeton University’s WordNet. Full sources and licences.
a skating figure that carves an 8 in the ice