Which word means to caution or advise against something?

The word that means to caution or advise against something is "admonish." This term is often used to convey a sense of warning or reproof, implying that there is a need to address someone's behavior or actions with a sense of concern. Admonishing can involve a gentle reminder or a firmer warning, but it essentially serves the purpose of guiding someone away from making an unwise choice. This makes "admonish" particularly suitable in contexts where one intends to prevent negative outcomes by advising caution.

In contrast, the other options do not convey the same meaning. "Temper" refers to moderating or restraining, often in terms of emotions or reactions. "Aver" means to affirm or assert something confidently, which does not involve cautioning or advising others. "Articulate" pertains to expressing thoughts and ideas clearly and effectively, rather than advising against an action. Therefore, "admonish" is the word that most accurately encapsulates the act of cautioning or advising someone against something.