Of or having to do with ganking. Commonly used by 1337-speakers (leet-speakers) and script kiddies. Gankage also refers to pwnage and laying waste to hordes of ninja and pirate enemies. Ganking is typically considered very uncool because it usually involves skanky tactics to lay the beatdown on an enemy.
See also: gank
OMFG, that Troll Rogue just set the Basin alight with utter gankage! There are ninja Alliance corpses everywhere!