caustic vs speaking one's mind

caustic

adj
  • Capable of burning, corroding or destroying organic tissue. 

  • Sharp, bitter, cutting, biting, and sarcastic in a scathing way. 

noun
  • The envelope of reflected or refracted rays for a given curve. 

  • Caustic soda. 

  • The envelope of reflected or refracted rays of light for a given surface or object. 

  • Any substance or means which, applied to animal or other organic tissue, burns, corrodes, or destroys it by chemical action; an escharotic. 

speaking one's mind

How often have the words caustic and speaking one's mind occurred in a corpus of books? (source: Google Ngram Viewer )