Which term captures the essence of troubling or afflicting someone?

The term that captures the essence of troubling or afflicting someone is "ail." This word is often used to describe a state of distress or suffering, whether physically, emotionally, or mentally. When someone is ailing, it implies that they are experiencing some form of difficulty or hardship that affects their well-being.

The other options describe different concepts and do not relate to the idea of affliction in the same way. "Jovial" describes a cheerful and friendly disposition, which is the opposite of being troubled. "Indict" refers to formally accusing someone of a crime, which pertains to legal processes rather than personal affliction. "Vilify" means to speak or write about someone in an abusively disparaging manner, but it does not inherently convey the idea of personal suffering or being troubled. Thus, "ail" is the most fitting choice that directly relates to the notion of affliction.