obsession vs whim

obsession

noun
  • An idea that engenders a compulsive or irrational preoccupation, or the preoccupation thereby engendered. 

  • The quality of being obsessed. 

  • Influence or control by evil spirits without possession. 

  • An activity or entity that inspires a compulsive and potentially unhealthy fixation, or the fixation thereby inspired. 

whim

noun
  • A fanciful impulse, or sudden change of idea. 

  • A bird, the Eurasian wigeon. 

  • A large capstan or vertical drum turned by horse power or steam power, for raising ore or water, etc., from mines, or for other purposes 

verb
  • To be seized with a whim; to be capricious. 

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