spleen

 
Pronunciation: /spliːn/

noun

  • 1 Anatomy an abdominal organ involved in the production and removal of blood cells in most vertebrates and forming part of the immune system.
  • 2 [mass noun] bad temper; spite: he could vent his spleen on the institutions which had duped him

Derivatives

spleenful

adjective

Origin:

Middle English: shortening of Old French esplen, via Latin from Greek splēn; spleen (sense 2) derives from the earlier belief that the spleen was the seat of bad temper