An Irish saying. A description of somebody's immediate ability to detect awareness, or knowledge of something. That something being on any end of the secretive or exclusive spectrum.
Eg. In a game of poker for instance. If player 1 sees a bluff in player 2. Player 1 simply looks at player 2, smiles, winks and says confidently, "Bang wide".
Eg. Finally nailing long division in school.
"Did you get a remainder?"
"Nah, I'm bang wide now!"
Eg. You're mate is trying to make you aware of an ass that deserves checking out. Unbeknownst to him, you've already seen it. When he attempts to let you in on the sighting, you casually reply "Bang wide, yeah!"
When someone or something does something you don't like or approve of, or pisses you off, tell them their wedge is nice. Can also be used for when someone does something stupid/humorous. Or for anything really.