WordNet records no synonym and no antonym for maxwell's demon. 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.
an imaginary creature that controls a small hole in a partition that divides a chamber filled with gas into two parts and allows fast molecules to move in one direction and slow molecules to move in the other direction through the hole; this would result in one part of the container becoming warmer and the other cooler, thus decreasing entropy and violating the second law of thermodynamics
Synonyms, antonyms and the broader and narrower relations for maxwell's demon come from Princeton University’s WordNet. Full sources and licences.