filly vs nymph

filly

noun
  • A young female horse. 

nymph

noun
  • A young girl, especially one who is attractive, beautiful or graceful. 

  • The larva of certain insects. 

  • Any female nature spirit associated with water, forests, grotto, wind, etc. 

  • Any of various butterflies of the family Nymphalidae. 

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