deism deisidaimonia • deist · · · Info · Definitions · Synonyms · Characters · · deism · · Text Latin · · Script 5 · · Length Definitions · · · (noun) the form of theological rationalism that believes in God on the basis of reason without reference to revelation. Synonyms: free thought. · · Noun Definition 1 Synonyms · · · free thought · · Synonym 1 Characters · · d latin small letter d U+0064 e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D s latin small letter s U+0073