impotent vs subnormal

impotent

noun
  • an impotent or powerless person 

  • a man who has erectile dysfunction 

adj
  • lacking physical strength or vigor; weak 

  • incapable of sexual intercourse, often because of an inability to achieve or sustain an erection, having impotentia coeundi 

  • lacking in power, as to act effectively; helpless 

  • sterile 

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 impotent and subnormal occurred in a corpus of books? (source: Google Ngram Viewer )