How would you describe someone who is "unscrupulous"?

Describing someone as "unscrupulous" indicates that they lack moral principles and are dishonest in their actions. This term suggests a willingness to act without regard for ethics or integrity, often doing whatever is necessary to achieve their goals, regardless of the consequences for others. The word encompasses behaviors that are deceptive or unprincipled, highlighting a disregard for what is generally accepted as right or wrong. This characterization fits well with the definition provided in the correct choice.

In contrast, the other descriptions imply a strong adherence to ethics and integrity, which do not align with the meaning of "unscrupulous." An ethical and principled person, for instance, would act in accordance with moral standards, making them the opposite of unscrupulous.