invalid vs null

invalid

adj
  • Intended for use by an invalid. 

  • Not valid; not true, correct, acceptable or appropriate. 

  • Suffering from disability or illness. 

verb
  • To make invalid or affect with disease. 

  • To exempt from (often military) duty because of injury or ill health. 

null

adj
  • Having no validity; "null and void". 

  • Insignificant. 

  • Causing a complete loss of gene function; amorphic. 

  • Absent or non-existent. 

  • Of the null set. 

  • Of or comprising a value of precisely zero. 

  • Neutral. 

verb
  • To crack; to remove restrictions or limitations in (software). 

  • To return to the null position, setting, etc. 

  • To form nulls, or into nulls, as in a lathe. 

noun
  • The null character; the ASCII or Unicode character (␀), represented by a zero value, which indicates no character and is sometimes used as a string terminator. 

  • Zero quantity of expressions; nothing. 

  • One of the beads in nulled work. 

  • A non-existent or empty value or set of values. 

  • Something that has no force or meaning. 

  • The attribute of an entity that has no valid value. 

  • The null hypothesis. 

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