What is Arbiter?
The covenant warrior that defeats Tartarus in halo 2.
The Arbiter can temporary cloak himself by pressing by pressing the white button (LB on xbox 360)
An arbiter is much like a Judge, the arbiter has the power to dicide a dispute or how to end one. An arbiter is also person that has the power of deciding
The arbiter from Halo 2 used the power to end a dispute regarding an uprising of heretics.
Gordon Freeman was put in an arbitrary position in Half-Life 2, he was used to end the dispute with the Combine
Arbiter Thel 'Vadam (formerly "Thel 'Vadamee"), often simply referred to as The Arbiter amongst players, was a distinguished Sangheili. At the apogee of his career with the Covenant he served as the Supreme Commander of the Fleet of Particular Justice. However, following the destruction of Installation 04, he was stripped of his rank, and forced to don the ancient armor of Arbiter. He accepted the position of Arbiter to continue his service to the Covenant, even in his disgraced state. The Arbiter is always sent on a suicidal mission to claim great honor in death, so he was not expected to live. However, the Hierarchs (and later the Jiralhanae that the Prophets used to attempt to assassinate the Arbiter) underestimated his skill, and he survived. He, along with the rest of the Sangheili, allied themselves with Humans, after the Gravemind told him of the Halo's true purpose, and was betrayed by his Covenant brethren. He later swore vengeance on The Prophet of Truth.
Simply, Arbiter is god.
When a person of the black or hispanic persuasion starts a fight in a store with employees or other customers to aid and cover the shoplifting efforts of other members of said person's group. Named after the Arbiter aircraft in Starcraft, a ship that makes nearby friendly units invisible.
Wow, Jose is such an arbiter. I heard that he punched out somebody at Best Buy so his friends could raid the Bargain Bin.