overman vs übermensch

overman

noun
  • A person with great powers; a superman. 

  • A person who supervises others; a supervisor, especially in a mine. 

verb
  • To provide with too many personnel; overstaff. 

übermensch

noun
  • A member of the proposed Aryan super race. 

  • An overman (“higher” man) who has overcome (transcended) his (mere) humanity. (There is no consensus regarding the exact nature of the figure of the übermensch in Nietzsche’s philosophy.) 

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