blood relative vs cousin

blood relative

noun
  • A person who is related to another through a common ancestor, and not merely by marriage or adoption. 

cousin

noun
  • Any relation who is not a direct ancestor or descendant but part of one's extended family; one more distantly related than an uncle, aunt, granduncle, grandaunt, nephew, niece, grandnephew, grandniece, etc. 

  • Something kindred or related to something else. 

  • The child of a person's uncle or aunt; a first cousin. 

  • A member of the British intelligence services (from an American perspective) or of the American intelligence services (from a British perspective). 

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