neither vs not

neither

adv
  • Similarly not. 

det
  • Not one of two; not either. 

  • Not either (used with nor). 

pron
  • Not either one of two. 

not

adv
  • To no degree. 

  • Negates the meaning of the modified verb. 

  • Used to indicate the opposite or near opposite, often in a form of understatement. 

  • ‘Do they know?’ ‘I believe not’ (formal) 

intj
  • Used to indicate that the previous phrase was meant sarcastically or ironically. 

conj
  • And not. 

How often have the words neither and not occurred in a corpus of books? (source: Google Ngram Viewer )