NEPTUNISM Antonyms There are 2 antonyms of the word neptunism. (opposite meanings)Did you mean?Definition of NEPTUNISMBest Opposite Words For NEPTUNISMTop 20Top 10 Top 20 (Default)Top 50 Top 100 All All (Default)WordsPhrases All All (Default)Verb Noun Adjective Adverb RankWordSave?Synonyms..UsageType1plutonismnounn2vulcanismnounn Alternatives for PLUTONISM Words (3)magmatismplutonismvulcanismOpposite words for plutonism Alternatives for VULCANISM Words (1)volcanicityOpposite words for vulcanism