lie back vs slummock

lie back

verb
  • To relax, to exert less effort 

  • To lie down from a sitting position 

slummock

verb
  • To behave lazily or indolently 

  • To behave awkwardly or clumsily 

noun
  • A slovenly person 

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