Blackguard (noun)

1. A person who is thoroughly dishonest and without morals or scruples.
2. A soldier who is assigned to guard prisoners or to perform other menial duties.

Origin:

Late 16th century: from black + guard, originally meaning 'a menial servant in a household', later 'a low or vicious person', also (in sense 2) 'a soldier guarding prisoners'. the original sense has given rise to the current sense.

Examples:

1. Many people consider politicians who take bribes to be blackguards, as they are seen as betraying the trust of their constituents.
2. Some people believe that people who engage in insider trading or other illegal activities are blackguards, as they take advantage of others for their own personal gain.
3. During World War I, blackguards were often responsible for escorting prisoners of war to and from detention camps.
4. Many people see blackguards as a danger to society, as they are willing to engage in criminal activities without any sense of morality or ethics.
5. Some historical accounts describe blackguards as rough, uneducated soldiers who were often more interested in their own comfort and well-being than in the welfare of their charges.