elfin vs water nymph

elfin

noun
  • An elf; an inhabitant of fairy-land. 

  • A little urchin or child. 

  • Any of the butterflies in the subgenus Incisalia of the North American lycaenid genus Callophrys. 

adj
  • Relating to or resembling an elf or elves, especially in its tiny size or features. 

water nymph

noun
  • A female spirit presiding over fountains, wells, streams, etc. 

  • Any of various aquatic plants of the genus Najas. 

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