'head-on' definitions:

Definition of 'head-on'

From: WordNet
adverb
In direct opposition; directly; "we must meet the problem head-on"
adverb
With the front foremost; "the cars collided head-on"
adjective
Characterized by direct opposition; "a head-on confrontation"
adjective
Meeting front to front; "a frontal attack"; "a head-on collision" [syn: frontal, head-on]

Definition of 'head-on'

From: GCIDE
  • head-on \head-on\ adj.
  • 1. characterized by direct opposition; as, a head-on confrontation.
  • Syn: head-to-head. [WordNet 1.5]
  • 2. Without evasion or compromise; as, his usual head-on fashion; to meet a problem head-on.
  • Syn: downright, flat-footed, forthright, foursquare, straightforward. [WordNet 1.5]
  • 3. Meeting front to front; used mostly of collisions between vehicles; as, a head-on automobile collision.
  • Syn: frontal. [WordNet 1.5]