What term describes a corrupt or depraved act or practice?

The term that describes a corrupt or depraved act or practice is "turpitude." This word comes from the Latin "turpitudo," meaning "baseness" or "depravity," and it is often used in legal contexts to refer to conduct that is inherently vile or morally reprehensible. In societal discussions, "turpitude" suggests actions or behaviors that deviate sharply from accepted ethical standards, highlighting a profound moral failing.

In contrast, the other options do not reflect this meaning. "Tyro" refers to someone who is inexperienced or a beginner in a particular field, which does not convey any notion of corruption or depravity. "Usury" describes the practice of lending money at excessively high-interest rates, which relates more to financial exploitation rather than a general act of moral corruption. "Vaunt," on the other hand, means to boast or brag about something, lacking any implication of corruption or immoral behavior. Thus, "turpitude" is the term that best captures the essence of a corrupt or depraved act.