acerbation vs unease

acerbation

noun

  • Bitterness of feeling. 

  • Exacerbation, aggravation, deterioration. 

unease

noun

  • Trouble; misery; a feeling of disquiet or concern. 

verb

  • To make uneasy or uncomfortable 

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