death march vs keen

death march

noun
  • Synonym of dead march (“mournful music for a funeral etc.”) 

  • A forced movement of people, on foot, in such circumstances that many die during the journey. 

  • A project that requires a stretch of unsustainable overwork, or whose participants feel it is destined to fail. 

keen

noun
  • A prolonged wail for a deceased person. 

verb
  • To utter with a loud wailing voice or wordless cry. 

  • To mourn. 

  • To make cold, to sharpen. 

  • To utter a keen. 

adj
  • Often with a prepositional phrase, or with to and an infinitive: showing a quick and ardent responsiveness or willingness; eager, enthusiastic, interested. 

  • Acute of mind, having or expressing mental acuteness; penetrating, sharp. 

  • Having a fine edge or point; sharp. 

  • Of cold, wind, etc.: cutting, penetrating, piercing, sharp. 

  • Of prices, extremely low as to be competitive. 

  • Acrimonious, bitter, piercing. 

  • Fierce, intense, vehement. 

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