condense vs stiffen

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. 

stiffen

verb
  • To make stiff. 

  • To become stiff. 

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