boot boy vs practical joker

boot boy

noun
  • A boy who cleans boots and shoes. 

  • A boy who cares for a footballer's boots. 

  • One of a gang of violent hooligans who usually wear short-cropped hair and bovver boots. 

practical joker

noun
  • someone who instigates practical jokes 

How often have the words boot boy and practical joker occurred in a corpus of books? (source: Google Ngram Viewer )