Duff vs Slick

Duff

name
  • A male given name 

  • An unincorporated community in Tennessee, United States 

  • An unincorporated community in Indiana, United States 

  • A village in Saskatchewan, Canada 

  • A surname. 

Slick

name
  • A term of address, generally applied to males, possibly including strangers, implying that the person addressed is slick in the sense of "sophisticated", but often used sarcastically. 

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