forlorn vs singing the blues

forlorn

noun

  • A forlorn hope. 

  • A member of a forlorn hope. 

adj

  • Abandoned, deserted, left behind. 

  • Unlikely to succeed; hopeless. 

  • Pitifully sad, wretched, miserable; lonely, especially from feeling abandoned, deserted, forsaken. 

singing the blues

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