to be bothered by something to the point of severe jaw clenching causing your chin to stick out like a jay leno chin.
What did you say to Dee to piss her off so bad? She's been all chin today. whatta whore...
A weirdo who allways insists on showing off HIS new toys. He is really a child inside, who flirts with his best friends constantly like a perv.
An allchin is allways a nobhead.
An example of this would be him showing of a new car or a new gadget such as a new ipod which he can only afford of his grandmas catalogue. An allchin thinks he is sooo posh because he works in a high profile company such as Yorkshire Bank or Barclays Bank. But every one knows he often started of in a place like McDonalds or a pound shop.