loneliness vs solitude

loneliness

noun
  • The condition or state of being alone or having no companions. 

  • The state of being unfrequented or devoid of human activity (of a place or time). 

  • A feeling of depression resulting from being alone or from having no companions. 

solitude

noun
  • Aloneness; the state of being alone, solitary, or by oneself. 

  • A lonely or deserted place. 

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