neither vs too

neither

adv
  • Similarly not. 

det
  • Not one of two; not either. 

  • Not either (used with nor). 

pron
  • Not either one of two. 

too

adv
  • Likewise. 

  • Used to contradict a negative assertion. 

  • To an excessive degree; over; more than enough. 

  • Also; in addition. 

  • To a high degree, very. 

How often have the words neither and too occurred in a corpus of books? (source: Google Ngram Viewer )