What term is used to formally accuse someone of or charge them with a serious crime?

The term used to formally accuse someone of or charge them with a serious crime is "indict." This legal process typically involves a grand jury reviewing evidence presented by a prosecutor and deciding whether there is sufficient evidence to formally charge an individual with a crime. An indictment signifies that the grand jury believes there is enough evidence to proceed with a criminal case, thus emphasizing its role as a serious legal action indicative of criminal charges.

In contrast, the other terms do not have legal implications of formally charging someone with a crime. "Vilify" refers to speaking or writing about someone in an abusively disparaging manner, but does not carry any formal legal weight. "Ail" is related to suffering or experiencing discomfort, and "delusion" pertains to a false belief held despite evidence to the contrary, which also does not apply to the context of formally charging someone with a crime.