mild vs piercing

mild

adj
  • Moderately warm, especially less cold than expected. 

  • Not sharp or bitter; not strong in flavor. 

  • Of only moderate severity; not strict. 

  • Not serious or dangerous. 

  • Gentle and not easily angered. 

  • Not overly felt or seriously intended. 

  • Acting gently and without causing harm. 

noun
  • A relatively low-gravity beer, often with a dark colour; mild ale 

piercing

adj
  • Of temperature, extremely cold so that it penetrates through clothing and shelter. 

  • Appearing to look deeply into; penetrating. 

  • Of sound, loud and sharp; shrill. 

noun
  • A hole made in the body so that jewellery can be worn through it. 

  • An item of jewellery designed to be fitted through a piercing (sense 2). 

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