WordNet records no synonym and no antonym for stooper. 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 person at a racetrack who searches for winning parimutuel tickets that have been carelessly discarded by others
a person who carries himself or herself with the head and shoulders habitually bent forward
Synonyms, antonyms and the broader and narrower relations for stooper come from Princeton University’s WordNet. Full sources and licences.