on time vs retarded

on time

prep
  • By installments, payments over a period of time. 

  • By a player's running out of time. 

  • Punctually or according to the schedule. 

adj
  • Punctual or according to schedule. 

retarded

adj
  • Delayed; delayed in development, hindered; impeded. 

  • Designating a parameter of an electromagnetic field which is adjusted to account for the finite speed of radiation. 

  • Extremely stupid. 

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