bengali has 1 distinct synonym spread across 1 of its 4 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.
(Hinduism) a member of a people living in Bangladesh and West Bengal (mainly Hindus)
an ethnic group speaking Bengali and living in Bangladesh and eastern India
a Magadhan language spoken by the Bengali people; the official language of Bangladesh and Bengal
1 of the 4 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for bengali.
Synonyms, antonyms and the broader and narrower relations for bengali come from Princeton University’s WordNet. Full sources and licences.