civilization has 3 distinct synonyms spread across 4 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 society in an advanced state of social development (e.g., with complex legal and political and religious organizations)
“the people slowly progressed from barbarism to civilization”
the social process whereby societies achieve an advanced stage of development and organization
a particular society at a particular time and place
“early Mayan civilization”
the quality of excellence in thought and manners and taste
“a man of intellectual refinement”
Synonyms, antonyms and the broader and narrower relations for civilization come from Princeton University’s WordNet. Full sources and licences.