on guard vs safely

on guard

adj
  • The starting position of a fencing bout; en garde. 

  • Transmitting on the aircraft emergency frequency. 

  • Vigilant, alert. 

safely

adv
  • In a safe manner; without risk; using caution above all else. 

  • In a secure manner; without the possibility of injury or harm resulting. 

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