emergency vs necessity

emergency

noun
  • Arising from or used in an emergency. 

  • A situation which poses an immediate risk and which requires urgent attention. 

  • An individual brought in at short notice to replace a member of staff, a player in a sporting team, etc. 

  • The department of a hospital that treats emergencies. 

necessity

noun
  • Something necessary; a requisite; something indispensable. 

  • Something which makes an act or an event unavoidable; an irresistible force; overruling power. 

  • Greater utilitarian good; used in justification of a criminal act. 

  • Indispensable requirements (of life). 

  • The negation of freedom in voluntary action; the subjection of all phenomena, whether material or spiritual, to inevitable causation; necessitarianism. 

  • The condition of being needy; desperate need; lack. 

  • The quality or state of being necessary, unavoidable, or absolutely requisite. 

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