abet vs retard

abet

verb
  • To support, countenance, maintain, uphold, or aid (any good cause, opinion, or action); to maintain. 

  • To incite; to assist or encourage by aid or countenance in crime. 

retard

verb
  • To put off; to postpone. 

  • To decelerate; to slow down. 

  • To keep delaying; to continue to hinder; to prevent from progressing. 

noun
  • Retardation; delay. 

  • A slowing down of the tempo; a ritardando. 

  • A person or being who is extremely stupid or slow to learn. 

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