theologian vs theologus

theologian

noun
  • In Roman Catholic usage, a theological lecturer attached to a cathedral church. 

  • In Eastern Orthodox usage, a person who has had direct experience of and unity with God. 

  • One who studies theology. 

theologus

noun
  • Synonym of theologian (“Roman Catholic lecturer”) 

How often have the words theologian and theologus occurred in a corpus of books? (source: Google Ngram Viewer )