Inting stands for "intentional feeding" and describes an action where a player loses on purpose to harm his own team.
"Intentional" because losing is a free decision on the player's part in question and "feeding" because it feeds the opponent with gold and experience.
The so-called "inting" has its origin in League Of Legends, but today it is also observed in many other communities and used as a collective word for a variety of actions.
Originally it was used to describe someone who dies continuously on purpose to harm his team and to troll the teammates. Nowadays, "inting" or "inten" is used for all sorts of things and has almost lost its original meaning. Today it is used for example when players die, position themselves wrongly, simply play badly or make many mistakes.
The inten was made famous by Tyler1, one of the greatest LOL streamers of all time. The latter used to be notorious for immediately inking when a game didn't go to his liking or he didn't like a teammate. In this case, he often tended to just run into the opponent's tower in the middle and abandon the game on purpose.
Today, inting is an offense for which many players, like Tyler1 in his time, are banned. Because unfortunately the inting of fellow players always brings LOL fans to concentrate on another game, which is why Riot Games punishes the inting meanwhile very hard.
For this reason, "soft inting" has developed over the years, a tactic with the same goal, but where you try to lose inconspicuously and by making stupid mistakes and troll your fellow players.