rivet has 6 distinct synonyms spread across 2 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
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.
hold (someone's attention)
“The discovery of the skull riveted the paleontologists”
ornament consisting of a circular rounded protuberance (as on a vault or shield or belt)
heavy pin having a head at one end and the other end being hammered flat after being passed through holes in the pieces that are fastened together
Synonyms, antonyms and the broader and narrower relations for rivet come from Princeton University’s WordNet. Full sources and licences.