aquarius 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.
(astrology) a person who is born while the sun is in Aquarius
a zodiacal constellation in the southern hemisphere; between Capricornus and Pisces
Synonyms, antonyms and the broader and narrower relations for aquarius come from Princeton University’s WordNet. Full sources and licences.
the eleventh sign of the zodiac; the sun is in this sign from about January 20 to February 18