poor relation vs subnormal

poor relation

noun

  • Something seen as inferior. 

subnormal

noun

  • A person whose abilities are less than normal. 

  • That part of the axis of a curved line which is intercepted between the ordinate and the normal. 

adj

  • denormal 

  • Less than normal. 

How often have the words poor relation and subnormal occurred in a corpus of books? (source: Google Ngram Viewer )