face to face vs head-on

face to face

adv
  • Closely encountering (a thing or situation). 

  • In person; directly; in the physical presence of somebody. 

head-on

adv
  • With direct confrontation. 

  • With the front of a vehicle. 

noun
  • A collision from the front. 

adj
  • Of a collision, from the front or in the direction of motion. 

  • Direct, abrupt, blunt or unequivocal; not prevaricating. 

How often have the words face to face and head-on occurred in a corpus of books? (source: Google Ngram Viewer )