by 2000 as the verb that indicates the situation of many players or NPCs simultaneously attacking one; gamer slang, perhaps borrowed from hip-hop and drug-abuse slang (where it is attested by 1995 in [..]

   kill

Suggests it was an easy victory. Usually meant as an insult.

Abbreviation for Gang Kill, but over time the term has come to refer to any time a hero or group of heroes attempts to pick off an enemy hero (or enemy heroes) by surprise, but usually with superior f [..]

To be ganked is to have your character killed by unfairly overwhelming odds – e.g. six vs one with all players at the same level or one-on-one but one player is twenty levels above the other.

Verb. To be ganked is a term referring to one player being overwhelmed and killed by a large group. Can be either by a group of other players doing player-kill or a group of NPC monsters. Used in a se [..]

Player vs. Player: To attack another player while they're trying to fight a monster.

To ambush enemies with one or more champions. Example: “OMG WE NEED A GANK WHERE IS OUR JUNGLER I SWEAR TO GOD I’M GONNA START FEEDING!” 

To kill another player by surprise.

Helping the team to kill the enemy. If you tell someone to attack the enemy, you ask for a gank.

Ganking means stealing something from someone else, usually when they're not by their computer playing.

To show up (usually unexpected) in a lane that you aren't "supposed" to be in, typically in an attempt to catch the enemy unaware and get a kill.