WordNet records no synonym and no antonym for right of way. 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.
the privilege of someone to pass over land belonging to someone else
the right of one vehicle or vessel to take precedence over another
the passage consisting of a path or strip of land over which someone has the legal right to pass
Synonyms, antonyms and the broader and narrower relations for right of way come from Princeton University’s WordNet. Full sources and licences.