A knife with blades or tools that the user can fold or retract into its handle, and of a size small enough for carrying safely and handily in a pocket, especially when suited to heavier duty uses or ad hoc applications outdoors or in workshops.
A folding knife with a blade which opens automatically (under spring pressure) when a button is pressed.
To (cause to) make a sudden move or transition.
To attack or cut with a switchblade.
To spring open or up.