croon vs tearjerker

croon

noun
  • A soft or sentimental hum or song. 

verb
  • To make a continuous hollow moan, as cattle do when in pain. 

  • To say softly or gently 

  • To hum or sing softly or in a sentimental manner. 

  • To soothe by singing softly. 

tearjerker

noun
  • An emotionally charged film, novel, song, opera, television episode, etc., usually with one or more sad passages or ending, so termed because it suggests one is likely to cry during its performance. 

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