coadjuvant vs collegial

coadjuvant

adj
  • cooperating 

noun
  • An adjuvant. 

collegial

adj
  • Of, relating to, or ruled by colleagues. 

  • Of or relating to a college or its students; collegiate. 

  • Ruled by bishops having equal power. 

  • Possessing adherence to the ethos, standards and conduct that govern behavior among colleagues within a given organization or profession. 

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