condense vs harden

condense

verb
  • To concentrate toward the essence by making more close, compact, or dense, thereby decreasing size or volume. 

  • To be transformed from a gaseous state into a liquid state. 

  • To transform from a gaseous state into a liquid state via condensation. 

harden

verb
  • To strengthen. 

  • To become or make (a person or thing) resistant or less sensitive. 

  • To become or make (a consonant) more fortis; to (cause to) undergo fortition. 

  • To make something hard or harder (tough, resistant to pressure). 

  • To modify (a website or other system) to make it resistant to malicious attacks. 

  • To unpalatalize or velarize. 

  • To become hard (tough, resistant to pressure). 

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