prolific vs unfruitful

prolific

adj
  • Similarly producing results or performing deeds in abundance 

  • Fertile; producing offspring or fruit in abundance — applied to plants producing fruit, animals producing young, etc. 

  • Of a flower: from which another flower is produced. 

unfruitful

adj
  • Not bearing fruit. 

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