“Gank” is a gaming term used most predominantly in MMOs like World of Warcraft or MOBAs like Dota 2. It is a portmanteau of the words “gang kill”, referring to when a group of players (usually higher level) gang up on a lone player and kill him through the element of surprise or superior numbers.
Some Redditors have suggested that it could also originate from the phrase “group flank”, which is also roughly the same meaning — a group of players attacking a lone player from an unexpected angle or ambush spot, resulting in a quick surprise kill.
Note that the term “gank” does not have to be strictly applied to a group of players. It can also be used to describe a one-on-one surprise attack.
Eg. I got ganked at Hellfire Peninsula by a higher level Pandaren.
It’s very difficult to determine exactly when “gank” came into popular usage, or which game community first coined the phrase. It was already in use when Ultima Online (1997) came about — and that game itself has one of the most notorious examples of widespread ganking within the game world.
But if you’ve ever played any online MMO, be it WoW, or Runescape, or any sort of game that allows PvP combat in a mixed area, then chances are you’ve experienced ganking before. It’s part and parcel of the MMO experience.