A portmanteau of the words "boost" and "nuke". It is the act of getting a boosted nuke in the Modern Warfare 2 video game.
To obtain a booke, one player enters a random Free-for-All match, and when there's an extra slot open, the other player joins in and they both go hide somewhere on the map. Once they find a
good hiding place, they begin exchanging kills, with the help of
tactical insertion, until one of them achieves a 25 killstreak (or 24 using hardline) which is of course a tactical nuke.
In this case, it's not an actual nuke but only a 'booke' because it was boosted and wasn't achieved by normal means.
The most important things boosters must have:
Equipment -
Tactical Insertion (If they don't have this, then they're pretty fuckin' stupid)
Perk 1 - Scavenger
Perk 2 - Cold-Blooded
Perk 3 - Ninja
Death Streak - Copycat