head-on vs precipitant

head-on

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

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

adv
  • With the front of a vehicle. 

  • With direct confrontation. 

noun
  • A collision from the front. 

precipitant

adj
  • Sudden or unexpected. 

  • That falls headlong, or causes a headlong fall. 

  • Rash or impulsive. 

  • That causes precipitation. 

noun
  • A substance that forms a precipitate when added to a solution. 

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