"A person noted for feats of courage or nobility of purpose, especially one who has risked or sacrificed his or her life." [Free Dictionary]. The Washington Post depicts such a person - the Taxi Commissioner and former Washington DC cop. [D.C. taxi official turned FBI informant recalls role in corruption probe].
Who would have thought that there would be so much money in taxi licenses? $250,000 from corrupt business people seeking control over the local taxi industry. But instead of being on the take and enticed by the 'cash.' he chose to go one better and become part of the solution. He became an informant, first for the DC police and subsequently for the FBI as they took over the case.
This was no short term event - it took 2 years of his life that could have easily been ended by one wrong step by himself or the FBI. E.g., "Once, he chastised an agent for repeatedly driving through his meeting place in a conspicuous Ford Crown Victoria." One can bet that it was shiny clean.
The story reads of feats of courage, nobility of purpose, risk and sacrifice of life. So what was his reward?
Washington Post:: "The voluble former D.C. police officer, a bespectacled 59-year-old retiree who shuffles because he has two wrecked knees, received not a dime, nor even a mention in self-congratulatory press releases issued by federal authorities. Stress wrecked his sleep, binge eating hoisted 60 pounds onto his considerable build, and his close-cropped hair and mustache turned increasingly gray. When his boss lost reelection, he was pushed out of his job"