A person that becomes frustrated or angry when playing a game.
Person A is being killed over and over again in a game by Person B e.g. In a first person shooter like Call of Duty Modern Warfare 2. This causes frustration and sheer anger towards Person B killing you repeatingly thus the term gamer rage. This anger is displayed through verbal means via a headset or chat with examples like:
"Oh my god you fucking camper"
"You fucking sprayer"
"Oh my god your such a lagger"
With generally explict verbal communication or verbal speech that creates a denial sense as to why Person A is constantly dying.