barricade has 8 distinct synonyms spread across 3 of its 5 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.
prevent access to by barricading
“The street where the President lives is always barricaded”
a barrier (usually thrown up hastily) to impede the advance of an enemy
“they stormed the barricade”
Synonyms, antonyms and the broader and narrower relations for barricade come from Princeton University’s WordNet. Full sources and licences.