gulf war syndrome has 1 distinct synonym spread across 1 of its 1 sense. 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.
a medical condition of uncertain origin that affected many veterans of the 1991 Gulf War; characterized by fatigue and headache and dizziness and nausea and rashes and joint pain and respiratory disorders
Synonyms, antonyms and the broader and narrower relations for gulf war syndrome come from Princeton University’s WordNet. Full sources and licences.