What term refers to warm approval or praise?

The term that refers to warm approval or praise is "approbation." This word is often used in contexts where someone is expressing approval or favorable judgment, whether in formal settings or everyday language. Appropriately, it conveys a sense of endorsement or commendation.

In contrast, the other terms provided do not align with the definition of praise. "Assiduous" refers to showing great care and perseverance, usually in work or effort. "Bellicose" describes a tendency to argue or fight, reflecting an aggressive or hostile attitude. "Anachronistic" pertains to something that is out of its proper time period, often leading to confusion regarding historical context. These distinctions illustrate that "approbation" is the most suitable choice for conveying warm approval or praise.