Nomer is a shortened version of the derogatory slang term no namer, often used by persons of reputation within a community to describe those who are lesser known. It can also be used to describe a newbie. It was first used in close-knit, online gaming communities by players who had achieved a revered status, due to their skill or achievements, to describe fellow gamers who were comparitively unknown or lacking in skill.
"Who does this nomer think he is?" or "We're totally gonna own these nomers."