WordNet records no synonym and no antonym for pantheism. It is the only member of each of its synsets, 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.
(rare) worship that admits or tolerates all gods
the doctrine or belief that God is the universe and its phenomena (taken or conceived of as a whole) or the doctrine that regards the universe as a manifestation of God
Synonyms, antonyms and the broader and narrower relations for pantheism come from Princeton University’s WordNet. Full sources and licences.