routine vs unformal

routine

adj
  • Ordinary with nothing to distinguish it from all the others. 

  • According to established procedure. 

  • Regular; habitual. 

noun
  • A course of action to be followed regularly; a standard procedure. 

  • A set piece of an entertainer's act. 

  • A set of normal procedures, often performed mechanically. 

  • A set of instructions designed to perform a specific task; a subroutine. 

unformal

adj
  • Not formal. 

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