forlorn hope

Meanings

1. A small troop of soldiers picked to make an advance attack, or the first attack; a storming party.
2. In the plural form forlorn hopes: the soldiers collectively making up such a troop; (by extension) a group of reckless adventurers.
3. Any dangerous or hopeless venture.

Etymology

Sense 1 (“troop of soldiers picked to make an advance attack, or the first attack”) is a mistranslation of Dutch verloren hoop (literally “lost troop”): verloren (“lost”, adjective) + hoop (“(obsolete) unit of soldiers, contingent; heap, pile, stack”), mistaking the latter word for the homograph hoop (“hope”). Verloren is the past participle of verliezen (“to lose (possession); to be defeated, to lose (a game)”) (ultimately from Proto-Germanic *fraleusaną (“to cease to have, lose”), from Proto-Indo-European *per- (“before, in front; first”) + *lewH- (“to cut, sever; to separate; to loosen; to lose”)), while hoop is ultimately from Proto-Germanic *haupaz (“a crowd, throng; a heap, pile”), from Proto-Indo-European *kouHp-nó- or *keHup-. Sense 2 (“dangerous or hopeless venture”) is either an extension of the meaning of sense 1, or from the literal meaning of the words forlorn and hope.