reward has 9 distinct synonyms spread across 6 of its 8 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. Its one recorded opposite is penalty.
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 recompense for worthy acts or retribution for wrongdoing
“the wages of sin is death”
payment made in return for a service rendered
an act performed to strengthen approved behavior
strengthen and support with rewards
Synonyms, antonyms and the broader and narrower relations for reward come from Princeton University’s WordNet. Full sources and licences.
“Let's reinforce good behavior”