edge has 11 distinct synonyms spread across 6 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 line determining the limits of an area
a sharp side formed by the intersection of two surfaces of an object
“he rounded the edges of the box”
a slight competitive advantage
“he had an edge on the competition”
Synonyms, antonyms and the broader and narrower relations for edge come from Princeton University’s WordNet. Full sources and licences.