Definitions by woodfella
Gack
A Gack is any item (other than a bottle opener) which is used to open a beer bottle. This applies only to bottles filled with beer. Soda, juice, de-alcoholized beer etc. do not apply. It must also not be a screw-off bottle. Due to the skill involved, a person who is rather adept at using various items to open a beer is referred to as a Gacksmith.
Gacksmith
A Gacksmith is a person who is skilled at removing the cap from a beer bottle by using an item other than a bottle opener. Lighters, pens, sheets of paper folded many times and rocks are just a few of the tools commonly used by a skilled Gacksmith. An item used successfully by a Gacksmith is known as a Gack.