protective 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 one recorded opposite is unprotective.
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.
intended or adapted to afford protection of some kind
“a protective covering”
2 of the 3 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 protective.
Synonyms, antonyms and the broader and narrower relations for protective come from Princeton University’s WordNet. Full sources and licences.