guts vs spine

guts

noun
  • Courage; determination. 

  • The center of the field. 

  • Content, substance. 

  • One's innermost feelings. 

  • The entrails or contents of the abdomen. 

  • The essential, core parts. 

  • The ring in the gambling game two-up in which the spinner operates; the centre. 

verb
  • To show determination or courage (especially in the combination guts out). 

  • To eat greedily. 

spine

noun
  • Courage or assertiveness. 

  • The stiffness of an arrow. 

  • The narrow, bound edge of a book that encloses the inner edges of the pages, facing outwards when the book is on a shelf and typically bearing the title and the author's and publisher's name. 

  • The heartwood of trees. 

  • A pointed, fairly rigid protuberance or needlelike structure on an animal, shell, or plant. 

  • Something resembling a backbone, such as a ridge, or a long, central structure from which other structures radiate. 

  • A series of bones situated at the back from the head to the pelvis of a human, or from the head to the tail of an animal, enclosing the spinal cord and providing support for the thorax and abdomen. 

  • A linear payscale operated by some large organizations that allows flexibility for local and specific conditions. 

  • A tall mass of viscous lava extruded from a volcano. 

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