White-knuckle is an adjective which means characterized by extreme nervousness or fear. White-knuckle is a term derived from the appearance of blood-drained fists, clenched tightly around something, such as a fairground ride.

"White-knuckle" refers to a state of extreme anxiety or tension, often associated with situations that are perceived as dangerous or high-stress. The term comes from the physical response of gripping an object so tightly that the knuckles turn white.

In psychology, the term "white-knuckle" can be used to describe various situations or experiences that produce intense anxiety or fear, such as:

• White-knuckle driving: This refers to driving in hazardous conditions, such as heavy rain or snow, or driving on treacherous roads or steep mountain passes. Drivers may experience a heightened sense of anxiety or tension, gripping the steering wheel tightly and feeling their knuckles turn white.

• White-knuckle flying: This refers to experiencing intense fear or anxiety while flying, often due to a fear of flying, turbulence, or a sense of loss of control. Passengers may experience physical symptoms of anxiety, such as sweating, shaking, or hyperventilating, and may grip their armrests or seat tightly.

• White-knuckle sports: This refers to extreme sports or activities that involve a high degree of risk, such as skydiving, bungee jumping, or rock climbing. Participants may experience a surge of adrenaline and intense fear or excitement, often resulting in a white-knuckle grip on their equipment.

Overall, the term "white-knuckle" is used to describe any situation that produces intense anxiety or fear, and may be associated with physical symptoms such as sweating, rapid heartbeat, and hyperventilation.