bag of nerves vs coward

bag of nerves

noun

  • A very nervous person. 

coward

noun

  • A person who lacks courage. 

adj

  • Cowardly. 

  • Borne in the escutcheon with his tail doubled between his legs. 

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