WordNet records no synonym and no antonym for fair hearing. It is the only member of its synset, 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.
a hearing that is granted in extraordinary situations where the normal judicial process would be inadequate to secure due process because the person would be harmed or denied their rights before a judicial remedy became available (as in deportation or loss of welfare benefits)
Synonyms, antonyms and the broader and narrower relations for fair hearing come from Princeton University’s WordNet. Full sources and licences.