like shooting fish in a barrel vs undifficult

like shooting fish in a barrel

prep
  • Extremely easy; sometimes with a connotation of triumph but at other times with a connotation of being meaningless and unsatisfying. 

undifficult

adj
  • Not difficult. 

How often have the words like shooting fish in a barrel and undifficult occurred in a corpus of books? (source: Google Ngram Viewer )