Scruple is the moral or ethical consideration that might inhibit certain actions in men. A politician without scruples, for instance, would be willing to do unethical things to achieve his goals. The adjective is scrupulous.
He hates shedding innocent blood, a scruple hard to maintain while outfitting a young man with an explosive-filled suicide vest. (Washington Post)
“The Financier” shocked America when it first came out, showing a central character, Frank Cowperwood (a composite of rapacious Gilded Age capitalists, like Collis Huntington, the brains behind Southern Pacific), who pursues money utterly without scruple. (Chicago Tribune)
