smart money has 2 distinct synonyms spread across 1 of its 3 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.
money bet or invested by experienced gamblers or investors (especially if they have inside information)
(law) compensation in excess of actual damages (a form of punishment awarded in cases of malicious or willful misconduct)
Synonyms, antonyms and the broader and narrower relations for smart money come from Princeton University’s WordNet. Full sources and licences.
people who are highly experienced or who have inside information
“the smart money said Truman would lose the election”