Particularly used to describe twats who drive a cheap crumby car put a noisy exhaust in it, obnoxiously loud sound system, lower it so that it no longer has suspension travel, more than likely a stupid looking rear spoiler/ wing to improve its aerodynamic grip at high speeds that it'll never achieve and put a big brand sticker on the back window. The driver will most likely be wearing a hat on backwards have one hand hanging out the door making possible gangster hand gesture all while thinking he is the shit.
Note: the vehicle is innocent in fact it's a victim. Don't hate what the car has become but hate the offender.
Bill: Jimmy! that's a fully sick Astra!
Jimmy: No bill, that's a shitbox driven by a wood duck
2. A creature that is often heard but is never seen
3. The sound made from a persons rectum after eating four or more plates of all-you-can-eat-ribs
Travis: "Nope, there must be a wood duck under the table"