standing has no recorded synonym. 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. Its 2 recorded opposites are running, seated.
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.
(of fluids) not moving or flowing
“mosquitoes breed in standing water”
executed in or initiated from a standing position
“race from a standing start”
(of persons) on the feet; having the torso in an erect position supported by straight legs
“standing room only”
social or financial or professional status or reputation
“of equal standing”
an ordered listing of scores or results showing the relative positions of competitors (individuals or teams) in a sporting event
the act of assuming or maintaining an erect upright position
3 of the 9 recorded senses carry no synonym, antonym or related term, so they are not shown above. Every sense, with its definition and examples, is on the full entry for standing.
Synonyms, antonyms and the broader and narrower relations for standing come from Princeton University’s WordNet. Full sources and licences.