spur has 11 distinct synonyms spread across 5 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.
tubular extension at the base of the corolla in some flowers
a railway line connected to a trunk line
incite or stimulate
“The Academy was formed to spur research”
Synonyms, antonyms and the broader and narrower relations for spur come from Princeton University’s WordNet. Full sources and licences.
strike with a spur
goad with spurs
“the rider spurred his horse”