bush league vs rookie

bush league

adj
  • Amateurish, unprofessional, unpolished, juvenile. 

  • Of inferior quality. 

noun
  • A professional sports association at the lower levels of minor league organization. 

  • A low-ranking or inferior level among groups, professions, organizations, etc. 

rookie

adj
  • non-professional; amateur 

noun
  • A type of firecracker, used by farmers to scare rooks. 

  • A novice. 

  • An athlete either new to the sport or to a team or in his first year of professional competition, especially said of baseball, basketball, hockey and American football players. 

  • An inexperienced recruit, especially in the police or armed forces. 

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