in- vs retro-

in-

prefix
  • Used with certain words to reverse their meaning 

  • in, into 

  • in, into, towards, within. 

  • Added to adjectives to mean not 

  • Added to nouns to mean lacking or without 

retro-

prefix
  • Back or backward. 

  • Behind. 

  • Pertaining to an earlier time. 

  • In the opposite direction. 

  • Old-fashioned or old school. 

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