corner has 9 distinct synonyms spread across 6 of its 14 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 place off to the side of an area
“he tripled to the rightfield corner”
an interior angle formed by two meeting walls
“a piano was in one corner of the room”
the intersection of two streets
“standing on the corner watching all the girls go by”
the point where three areas or surfaces meet or intersect
“the corners of a cube”
a temporary monopoly on a kind of commercial trade
“a corner on the silver market”
a predicament from which a skillful or graceful escape is impossible
“his lying got him into a tight corner”
a projecting part where two sides or edges meet
“he knocked off the corners”
a remote area
“in many corners of the world they still practice slavery”
gain control over
“corner the gold market”
Synonyms, antonyms and the broader and narrower relations for corner come from Princeton University’s WordNet. Full sources and licences.