With just a flick of the wrist, you go from harmless citizen to vicious, knife-weilding warrior. Same stigmas as a swithblade apply; see dangerous, lethal, scary and gangster. Although no more lethal than any other sharp object (see rock, nail and razor for examples), the media has turned it into something it never was.
Also called balisong or batanga. Not to be mixed with butterfly sword. A knife where the handle is in two parts, and the parts can be rotated around so they enclose the knife to hide the blade. With the right technique, very easy and fast to open. Illegal in many countries, because, like switchblades, they're easy to conceal. Baliswords also exist, often over two feet when opened.
I thought that I had a chance in this fistfight, until suddenly he had a butterfly knife in his hand. Luckily i brought my butterfly sword.
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).