representation has 7 distinct synonyms spread across 3 of its 10 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 presentation to the mind in the form of an idea or image
the act of representing; standing in for someone or some group and speaking with authority in their behalf
the state of serving as an official and authorized delegate or agent
a body of legislators that serve in behalf of some constituency
“a Congressional vacancy occurred in the representation from California”
a factual statement made by one party in order to induce another party to enter into a contract
“the sales contract contains several representations by the vendor”
a performance of a play
a statement of facts and reasons made in appealing or protesting
“certain representations were made concerning police brutality”
the right of being represented by delegates who have a voice in some legislative body
an activity that stands as an equivalent of something or results in an equivalent
Synonyms, antonyms and the broader and narrower relations for representation come from Princeton University’s WordNet. Full sources and licences.