WordNet records no synonym and no antonym for waikiki. 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 well-known beach and resort area on Oahu Island to the southeast of Honolulu
Synonyms, antonyms and the broader and narrower relations for waikiki come from Princeton University’s WordNet. Full sources and licences.