acridity vs mugwort

acridity

noun
  • An acrid taste or smell. 

  • Bitterness in speech or behaviour; causticness. 

  • Bitterness or acerbity. 

mugwort

noun
  • Artemisia vulgaris, traditionally used medicinally. 

  • Any of several aromatic plants of the genus Artemisia native to Europe and Asia. 

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