Is a slang word, used mainly in Ireland to describe a person who tries to be, and acts like a chav or its Irish counterpart - knacker.
They spend most of their time "hanging" around in groups acting "hard", desperately trying to get attention from a particularily classy breed of girl (or guy).
Often Shambags come from well off backgrounds and are very wealthy indeed, some even attending private schools! They desperately try to con everybody into thinking they are chavs so to appear tough, usually driven by low self-esteem.
They wear Burberry hats, Lacoste or Fred Perry tops (preferably striped horizontally), traksuit bottoms (often white) and white shoes with the laces tucked in the side and the tongue puled out over the end of the trouser leg
the word shambag comes from "sham" as in to con and "scumbag" - the look these people are trying to achieve
The Shambag race is growing rapidly and needs to be stopped, lets just hope they die out in a bloody war with the Emo