habitual vs retrofit

habitual

noun
  • A construction representing something done habitually. 

  • One who does something habitually, such as a serial criminal offender. 

adj
  • Pertaining to an action performed customarily, ordinarily, or usually. 

  • Of a person or thing: engaging in some behaviour as a habit or regularly. 

  • Of or relating to a habit; established as a habit; performed over and over again; recurrent, recurring. 

  • Regular or usual. 

retrofit

noun
  • An act of supplying a device, structure, etc., with new components or parts that were not previously available or installed; a retrofitting. 

  • A change made to a device, structure, etc., by introducing components or parts that were not previously available or installed. 

verb
  • To supply (a device, structure, etc.) with new components or parts that were not previously available or installed; to modernize. 

  • Synonym of backport (“to retroactively supply a fix or feature to a previous version of a software product at the same time or after supplying it to the current version.”) 

  • To give new characteristics or make alterations (to someone or something) to suit them to changed circumstances. 

  • To supply a device, structure, etc., with new components or parts that were not previously available or installed. 

  • To add or substitute (new components or parts) that were not previously available for or installed in a device, structure, etc. 

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