government has 8 distinct synonyms spread across 3 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.
the organization that is the governing authority of a political unit
“the government reduced taxes”
the act of governing; exercising authority
“regulations for the governing of state prisons”
(government) the system or form by which a community or other political unit is governed
“tyrannical government”
the study of government of states and other political units
Synonyms, antonyms and the broader and narrower relations for government come from Princeton University’s WordNet. Full sources and licences.