A perk in the Call of Duty series. This perk has only been used in Call of Duty: World at War and Call of Duty: Black Ops. It reduces explosive damage.
Damn, my grenade didn't slaughter that guy because he had Flak Jacket as one of his perks.
The act of putting on your sweater to reduce the risk of getting close to the gernade
When a fellow bro is about to take a gernade for another bro and might need some extra protection. So he throws on his sweater to reduce the damage taken.
John: dude look at that eye candy over there
Dave: man thats one narley gernade shes with
John: Bro i want her,.. you have got to help me out
Dave: god damm it, alright. give me a sec. gotta throw my flak jacket on
This is the asshole newb in Unreal Tournament Games that uses the flak cannon excessively , because its the only weapon he can use. Of course this being that splash damage does all the work. Anything with any sort of AIMING involved would clearly be to his/her detriment. Either way, He SUXORS