bush league vs bush-league

bush league

adj
  • Of inferior quality. 

  • Amateurish, unprofessional, unpolished, juvenile. 

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

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

bush-league

adj
  • Minor-league; second-rate. 

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