aggressor vs dastard

aggressor

noun
  • The person or country that first attacks or makes an aggression; that begins hostility or a quarrel; an assailant. 

dastard

noun
  • A malicious coward; a dishonorable sneak. 

adj
  • Meanly shrinking from danger, cowardly, dastardly. 

verb
  • To dastardize. 

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