polymorphous vs protean

polymorphous

adj
  • Having, or assuming, a variety of forms, characters, or styles 

  • Having, or occurring in, several distinct forms 

  • Crystallizing in two or more different forms; polymorphic 

protean

adj
  • Exceedingly variable; readily assuming different shapes or forms. 

noun
  • A protein that has been slightly modified by water, dilute acid, or enzymes, but not modified to the extent of a metaprotein. 

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