craven vs retromingent

craven

adj
  • Unwilling to fight; lacking even the rudiments of courage; extremely cowardly. 

noun
  • A coward. 

verb
  • To make craven. 

retromingent

adj
  • Cowardly. 

  • That urinates backwards; also used of such urination. 

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