ceaseless vs eternal

ceaseless

adj
  • Without an end. 

  • Without stop or pause, incessant. 

eternal

adj
  • Lasting forever; unending. 

  • existing outside time; as opposed to sempiternal, existing within time but everlastingly 

  • Constant; perpetual; ceaseless; ever-present. 

noun
  • One who lives forever; an immortal. 

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