British slang dating from World War II meaning to defecate, take a dump or shit. The phrase came about due to the heavy bombing of Dresden by the allies due to the concentration of military targets in and around the city. Dresden was also a centre of porcelain manufacture and since toilet bowls are made of porcelain, wartime humour made the connection, that and the societal requirement to use a polite euphemism, that if you went to take a crap you went to bomb Dresden.
A bombardier is the type of person that wears black air forces and adidas tracksuits and goes to gym and has tattoos.
Their job is usually being a loan shark and they talk in gypsy mixed w/ romanian, play soccer (badly but they love Jabulani), wear big sunglasses and cross gold chains.
Mike: Have you seen my wallet ?
Romeo: Nu varule sa mor de l-am vazut.
Dan: You're being such a bombardier Romeo.