cramming vs investigation

cramming

noun
  • An intensive course of hard study, as for an examination. 

  • The act by which something is crammed, or stuffed full. 

investigation

noun
  • The act of investigating; the process of inquiring into or following up; research, especially patient or thorough inquiry or examination 

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