study has 24 distinct synonyms spread across 11 of its 16 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 written document describing the findings of some individual or group
“this accords with the recent study by Hill and Dale”
a state of deep mental absorption
“she is in a deep study”
a room used for reading and writing and studying
“he knocked lightly on the closed door of the study”
attentive consideration and meditation
“after much cogitation he rejected the offer”
someone who memorizes quickly and easily (as the lines for a part in a play)
“he is a quick study”
a composition intended to develop one aspect of the performer's technique
“a study in spiccato bowing”
Synonyms, antonyms and the broader and narrower relations for study come from Princeton University’s WordNet. Full sources and licences.
think intently and at length, as for spiritual purposes
“He is meditating in his study”