vegetate has 1 distinct synonym spread across 1 of its 7 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.
lead a passive existence without using one's body or mind
establish vegetation on
“They vegetated the hills behind their house”
produce vegetation
“The fields vegetate vigorously”
grow like a plant
“This fungus usually vegetates vigorously”
grow or spread abnormally
“warts and polyps can vegetate if not removed”
propagate asexually
“The bacterial growth vegetated along”
Synonyms, antonyms and the broader and narrower relations for vegetate come from Princeton University’s WordNet. Full sources and licences.