Which term means to express criticism towards someone?

The term "upbraid" specifically means to criticize or scold someone sharply. It conveys a sense of reproach or reprimand, often implying that the criticism is justified or necessary. This word carries connotations of being direct and stern in the expression of disapproval, making it suitable for situations where one person is admonishing another for their actions or behavior.

In contrast, the other choices present different meanings. "Usury" refers to the practice of charging excessive interest on loans, which has no connection to expressing criticism. "Vaunt" means to boast or brag about something, often in an exaggerated manner, and does not imply a critical tone. "Succor" means to provide assistance or support, typically to those in distress, which is also unrelated to the concept of criticism. These distinctions clarify why "upbraid" is the term that most accurately fits the definition provided in the question.