nymphet vs water nymph

nymphet

noun
  • A sexually attractive girl or young woman. 

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 nymphet and water nymph occurred in a corpus of books? (source: Google Ngram Viewer )