cold fish vs inhuman

cold fish

noun
  • A heartless individual; a person lacking empathy and emotion. 

  • A sexual partner who, during sex, lacks vigor or emotional reciprocity. 

inhuman

adj
  • Transcending or different than what is human. 

  • Of or pertaining to inhumanity and the indifferently cruel, sadistic or barbaric behavior it brings. 

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