demolish has 7 distinct synonyms spread across 3 of its 4 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.
ruin or destroy
“his book demolishes an old myth”
Synonyms, antonyms and the broader and narrower relations for demolish come from Princeton University’s WordNet. Full sources and licences.
eat up completely, as with great appetite
“Some people can down a pound of meat in the course of one meal”
defeat soundly and humiliatingly
“The home team demolished the visitors”