melancholy vs suicidal

melancholy

adj
  • Affected with great sadness or depression. 

noun
  • Great sadness or depression, especially of a thoughtful or introspective nature. 

  • Black bile, formerly thought to be one of the four "cardinal humours" of animal bodies. 

suicidal

adj
  • Pertaining to suicide. 

  • Likely to commit, or to attempt to commit, suicide. 

  • Extremely reckless. 

  • Highly likely to certain to result in the deaths of the participants; dangerous or reckless to such a degree as to be tantamount to suicide for those taking part. 

noun
  • Someone suicidal; someone likely to kill themselves. 

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