lackluster vs subnormal

lackluster

noun
  • A person or thing of no particular brilliance or intelligence. 

  • Lack of brightness or points of interest. 

adj
  • Having no shine or lustre; dull. 

  • Not exceptional; not worthy of special merit, attention, or interest; having no vitality. 

  • Lacking brilliance or intelligence. 

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