frontal vs head-on

frontal

adj
  • Of, relating to, directed toward, or situated at the front. 

  • Of or relating to a weather front. 

  • Parallel to the main axis of the body and at right angles to the sagittal plane. 

  • Any of the scales of a reptile that lie in the general region of the forehead, more specifically between the eyes and to the anterior of this area. 

  • Directed against the front or at the main point or issue. 

  • Of or relating to the forehead or frontal bone. 

noun
  • A decorative drapery covering the front of an altar. 

  • The façade of a building. 

head-on

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

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

noun
  • A collision from the front. 

adv
  • With the front of a vehicle. 

  • With direct confrontation. 

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