restitution has 8 distinct synonyms spread across 2 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.
a sum of money paid in compensation for loss or injury
the act of restoring something to its original state
getting something back again
“upon the restitution of the book to its rightful owner the child was given a tongue lashing”
Synonyms, antonyms and the broader and narrower relations for restitution come from Princeton University’s WordNet. Full sources and licences.