WordNet records no synonym and no antonym for flaccid paralysis. It is the only member of its synset, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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.
weakness or loss of muscle tone resulting from injury or disease of the nerves innervating the muscles
Synonyms, antonyms and the broader and narrower relations for flaccid paralysis come from Princeton University’s WordNet. Full sources and licences.