accusation has 2 distinct synonyms spread across 2 of its 2 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 formal charge of wrongdoing brought against a person; the act of imputing blame or guilt
Synonyms, antonyms and the broader and narrower relations for accusation come from Princeton University’s WordNet. Full sources and licences.
an assertion that someone is guilty of a fault or offence
“the newspaper published charges that Jones was guilty of drunken driving”