Short for 'Arbitrary' - this acronym is used more commonly where the context of the word implies the likes of the target object/subject being 'random', 'strange', 'unusual', etc...
What an arb picture - looks like the guy's head is out of proportion with the rest of his body! And what's up with that pink porche in the background? Must be a photoshop.
by Dimitri Pappas July 22, 2008
An epic typo by Mabinogi NA player "archranger" of the Alexina server. This word was meant to be "Narb" but he failed so epicly it turned out as "Arb" and the term slowly developed into the frequently used word we know today, ARB!
1). Eddward is an ARB at cross dressing.
by Refuserishere July 29, 2011