trial by fire

Noun

trial by fire (countable and uncountable, plural trials by fire)

1. A test in which a person is exposed to flames in order to assess their truthfulness, commitment, courage etc.
   • “[I]t seems to me Fra Francesco is the greater hero, for he offers to enter the fire for the truth, though he is sure the fire will burn him.” . . .
     “It is true, Messer Segretario,” said the shopkeeper, with subdued impatience. “But will you favour us by interpreting the Latin?”
     “Assuredly,” said...1863, George Eliot, chapter 63, in Romola
   • And he pointed with his little assegai, the assegai handled with the royal wood, to where the fire glowed reddest—ay, he pointed and laughed. Then, my father, I grew cold indeed—yes, I grew cold who soon should be hot, for I saw the purpose of Chaka. He would put me to the trial by fire.1892, H. Rider Haggard, chapter 10, in Nada the Lily
2. A situation in which a soldier or other combatant faces the discharge of opposing weapons, as a test of their fortitude.
   • French troops, submitting to a trial by fire, drew toward the German forts, capturing and holding some machine-gun nests.1939 September 8, “Swiss Hear Heavy Guns”, in Reading Eagle, USA, retrieved 15 Jul 2012, page 8
   • Pork Chop Hill. Director Lewis Milestone . . . has produced a nerve-shattering study of how the American infantryman met his trial by fire in Korea.1959 June 22, “Cinema”, in Time
3. (broadly, idiomatic) Any ordeal which tests one's strength, endurance or resolve.
   • But take it all in all, the overland trail was a trial by fire. One gets a notion of its deadliness from the fact that over five thousand people died of cholera alone.1918, Stewart Edward White, chapter 5, in The Forty-Niners
   • Now, residents' legendary 100+-hour workweek may be on its way out. . . . Some doctors insist the long hours are a necessary trial by fire that produces highly skilled, virtually unflappable physicians.2001 June 18, Jessica Reaves, “Will Your Doctor Get More Reasonable Hours?”, in Time