Which word best describes a term meant for a niche audience?

The term "esoteric" effectively captures the essence of something that is intended for a niche audience. It refers to knowledge, concepts, or practices that are specialized and often only understood by a limited group of people who have specific interests or expertise. This aligns well with the idea of niche content, as it suggests that the subject matter may not be readily accessible or appreciated by the general public, but rather resonates with a specific subset of individuals who share a common background or interest.

The other terms do not convey the same meaning. A euphemism relates to the practice of substituting a mild or vague term for one considered harsh or blunt, which doesn’t pertain to the nature of audience specificity. Exonerate refers to the act of clearing someone from blame or fault, which is unrelated to audience targeting. Facetious describes a manner of joking or treating serious issues with deliberately inappropriate humor, which again does not connect to the concept of niche audiences. Thus, "esoteric" stands out as the most fitting descriptor for content aimed at a specific, often specialized audience.