flump vs plod

flump

verb
  • To move or fall heavily, or with a dull sound. 

  • To drop something heavily or with a dull sound. 

noun
  • A type of large marshmallow. 

  • A fat out-of-shape person. 

  • The dull sound so produced. 

plod

verb
  • To walk or move slowly and heavily or laboriously (+ on, through, over). 

  • To toil; to drudge; especially, to study laboriously and patiently. 

  • To trudge over or through. 

noun
  • A slow or labored walk or other motion or activity. 

  • the police, police officers 

  • a police officer, especially a low-ranking one. 

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