A fan of a certain thing who will tolerate no criticism of that thing. Most often associated with "nerdy" subjects, especially the video gaming community. Most people are likely to encounter fanboys over the Internet, as the veil of anonymity allows the fanboy to be as aggressive and arrogant as he likes without the possibility of reprisals.
Ordinary, well-adjusted game player: "Good game everyone."
Hulking, stinking, fast-food loving arrogant fanboy: "OMFG YOUR A NOOB LOL I COULD KICK UR ASS UR MOM (etc.)"
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