clock off vs shut down

clock off

verb
  • to leave work, especially by recording the leaving time on a machine 

  • Most of the staff have already clocked off for the night, you should do the same. 

shut down

verb
  • To pass (another vehicle), especially quickly. 

  • To close, terminate, or end. 

  • To turn off or stop. 

  • To emotionally withdraw into oneself as a defense mechanism; to block out external stressors. 

How often have the words clock off and shut down occurred in a corpus of books? (source: Google Ngram Viewer )