mantic vs portentous

mantic

adj

  • Relating to divination; prophetic. 

noun

  • A soothsayer, a seer. 

portentous

adj

  • Ominously prophetic. 

  • Of momentous or ominous significance. 

  • Puffed up with vanity. 

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