culprit

This term carries a strong connotation of guilt and blame. When applied to a person, it suggests a legal or moral transgression, often used in criminal investigations or disciplinary contexts to identify the specific individual who committed a wrong. When used to describe an inanimate object or a biological process, the word shifts toward a causal relationship. It identifies the primary agent responsible for a negative outcome, such as a mechanical failure or a health issue, framing the cause as an antagonist to be eliminated or corrected.