WordNet records no synonym and no antonym for jericho. 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 village in Palestine near the north end of the Dead Sea; in the Old Testament it was the first place taken by the Israelites under Joshua as they entered the Promised Land
Synonyms, antonyms and the broader and narrower relations for jericho come from Princeton University’s WordNet. Full sources and licences.