Absolute honesty and uprightness.
Example:
Her unquestioned probity helped win her the respect of her fellow judges.
Probity is a quality the American public generally hopes for in its elected officials but doesn't always get. Bankers, for example, have traditionally been careful to project an air of probity; the savings-and-loan scandal of the 1980s has made it even more necessary. An aura of probity surrounds such public figures as Walter Cronkite and Bill Moyers, men to whom many Americans would entrust their children and their finances.