Rejection

Rejection is a Halo: Reach multiplayer medal. Depicted as a gold diamond superimposed by a blue shield and brass padlock, the medal is earned by using Armor Lock and surviving a subsequent assault that would have otherwise been fatal, i.e. a plasma mortar launched from a Wraith. It was revealed alongside two other medals in Bungie's 07/09/10 weekly update.

Trivia

 * Ironically enough, if Armor Lock is used to destroy a vehicle you are not awarded a rejection medal. Which is strange considering the only way to destroy a vehicle using Armor Lock is to have a vehicle, going fast enough to splatter you, hit you head on. Meaning if you did not armor lock you would have surely died, and therefore, should properly award you the medal.
 * Oddly, one can earn this medal in Forge by setting the Damage Resistance to Invulnerable, walking into a Kill Ball, and activating Armor Lock.