Butterfly
Butterfly knife is legitimate trade tool vocabulary, neutral definition
A knife you can open and close by turning around the two sides of the grasp. Usually used in ghettos or for little assaults in quicky market. For the clever ones you can learn some tricks that make you look very very dangerous with that knife.
Damn, that guy has a butterfly in his pocket. Hope he won't use it.
Also in the dictionary
- butterfly in mining and extraction