foursquare has 3 distinct synonyms spread across 2 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.
with firmness and conviction; without compromise
“he stood foursquare for religious liberty and toleration”
(geometry) a plane rectangle with four equal sides and four right angles; a four-sided regular polygon
“you can compute the area of a square if you know the length of its sides”
2 of the 4 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for foursquare.
Synonyms, antonyms and the broader and narrower relations for foursquare come from Princeton University’s WordNet. Full sources and licences.