spineless vs weak-willed

spineless

adj
  • Cowardly, uncourageous; lacking character. 

  • Having no spines, prickles, or thorns. 

  • Having no spinal column. 

weak-willed

adj
  • irresolute, indecisive 

  • easily swayed 

How often have the words spineless and weak-willed occurred in a corpus of books? (source: Google Ngram Viewer )