cold fish vs impassive

cold fish

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

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

impassive

adj
  • Having, or revealing, no emotion. 

  • Still or motionless. 

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