1. 
2. 
[syn: frontal, head-on]
ADVERB (2)
1.  in direct opposition;  directly; 
- Example: "we must meet the problem head-on"
2.  with the front foremost; 
- Example: "the cars collided head-on"
The Collaborative International Dictionary of English v.0.48:
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]
WordNet (r) 3.0 (2006):
head-on
    adv 1: in direct opposition; directly; "we must meet the problem
           head-on"
    2: with the front foremost; "the cars collided head-on"
    adj 1: characterized by direct opposition; "a head-on
           confrontation"
    2: meeting front to front; "a frontal attack"; "a head-on
       collision" [syn: frontal, head-on]