cop-out vs cover story

cop-out

noun
  • An excuse made in order to avoid performing a task or duty; a reason offered when someone cops out. 

  • A person who cops out. 

  • Avoidance or inadequate performance of a task or duty; the action of copping out. 

cover story

noun
  • A fictitious account that is intended to hide one's real motive. 

  • A story included in a publication that is highlighted on the front cover. 

How often have the words cop-out and cover story occurred in a corpus of books? (source: Google Ngram Viewer )