What is "forlorn hope"

n. 1 (context military English) A small troop picked to make an advance attack, or the first attack; a storming party. 2 Any dangerous or hopeless venture.

n. a hopeless or desperate enterprise

A forlorn hope is a band of soldiers or other combatants chosen to take the leading part in a military operation, such as an assault on a defended position, where the risk of casualties is high. Such a band is also known as the "enfants perdus".