lessen vs maturate

lessen

verb
  • To make less; to diminish; to reduce. 

  • To become less. 

conj
  • unless. 

maturate

verb
  • To promote the perfect suppuration of (an abscess). 

  • To undergo perfect suppuration. 

  • To bring to ripeness or maturity; to ripen. 

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