What term refers to the act of making amends or atoning for a wrongdoing?

The correct term for the act of making amends or atoning for a wrongdoing is expiate. This verb specifically means to atone for guilt or sin, highlighting the process of seeking forgiveness or compensating for a fault. It carries a connotation of remorse and is often used in moral or ethical contexts where one seeks to alleviate the negative consequences of their actions.

In contrast, the other terms do not accurately relate to this concept. Expostulate refers to making a reasoned argument or expressing strong disapproval in an attempt to persuade someone. Effusive describes an expression of feelings in an unrestrained or heartfelt manner, often lacking a connection to wrongdoing. Expurgate means to remove material from a text that is considered objectionable or inappropriate, which does not align with the idea of atonement. Thus, expiate is the most fitting choice for the act of making amends for wrongdoing.