WordNet records no synonym and no antonym for ghetto. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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.
formerly the restricted quarter of many European cities in which Jews were required to live
“the Warsaw ghetto”
any segregated mode of living or working that results from bias or stereotyping
“the relative security of the gay ghetto”
a poor densely populated city district occupied by a minority ethnic group linked together by economic hardship and social restrictions
Synonyms, antonyms and the broader and narrower relations for ghetto come from Princeton University’s WordNet. Full sources and licences.