Definition from Wiktionary, the free dictionary
Alternative forms 
head-on (not comparable)
- (idiomatic) Direct, abrupt, blunt or unequivocal; not prevaricating.
- a head-on approach to a problem
- Of a collision, from the front or in the direction of motion.
- Getting into a head-on collision is dangerous.
head-on (plural head-ons)
Usage notes 
- The adjective is also head on, especially when appearing after the verb, as in
- She likes to tackle problems head on.