plop vs plunk

plop

verb
  • To land heavily or loosely. 

  • To make the sound of an object dropping into a body of liquid. 

  • To defecate. 

noun
  • A sound or action like liquid hitting a hard surface, or an object falling into a body of water. 

  • Excrement. 

intj
  • Indicating the sound of something plopping. 

plunk

verb
  • To land suddenly or heavily; to plump down. 

  • To pluck and quickly release (a musical string). 

  • To be a truant from (school). 

  • To intentionally hit the batter with a pitch. 

  • To croak. 

  • To drop or throw something heavily onto or into something else, so that it makes a dull sound. 

noun
  • The dull thud of something landing on a surface. 

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