WordNet records no synonym and no antonym for star drill. 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 steel rock drill with a star-shaped point that is used for making holes in stones or masonry; it is operated by hitting the end with a hammer while rotating it between blows
Synonyms, antonyms and the broader and narrower relations for star drill come from Princeton University’s WordNet. Full sources and licences.