WordNet records no synonym and no antonym for jigsaw puzzle. 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.
a puzzle that requires you to reassemble a picture that has been mounted on a stiff base and cut into interlocking pieces
Synonyms, antonyms and the broader and narrower relations for jigsaw puzzle come from Princeton University’s WordNet. Full sources and licences.