WordNet records no synonym and no antonym for walkabout. 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.
a public stroll by a celebrity to meet people informally
nomadic excursions into the bush made by an Aborigine
Synonyms, antonyms and the broader and narrower relations for walkabout come from Princeton University’s WordNet. Full sources and licences.