In order to loosen a bolt, turn it in a counter-clockwise direction. Turning a screw or bolt in a counter-clockwise direction to loosen it requires turning it to the left.
Hardware such as bolts and screws have a manufacturing process known as right threading. They are manufactured according to the right-hand rule. The turning of a bolt counter-clockwise is going outward or in the unit direction of vector (+k). Turning a bolt clockwise is going inward or in the unit direction of vector (-k). A good tip to remember when trying to tighten or loosen a bolt is that turning it right tightens and turning it left loosens.