paper has 6 distinct synonyms spread across 5 of its 9 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 material made of cellulose pulp derived mainly from wood or rags or certain grasses
Synonyms, antonyms and the broader and narrower relations for paper come from Princeton University’s WordNet. Full sources and licences.
an essay (especially one written as an assignment)
“he got an A on his composition”
a medium for written communication
“the notion of an office running without paper is absurd”
a scholarly article describing the results of observations or stating hypotheses
“he has written many scientific papers”
a business firm that publishes newspapers
“Murdoch owns many newspapers”