What term refers to an interest where economic loss would be suffered from an adverse event affecting the subject?

The term that best fits the description of an interest where economic loss would be suffered from an adverse event affecting the subject is "Insurable Interest." This concept is fundamental in insurance, as it establishes the policyholder's legitimate interest in the preservation of the insured item or individual.

To have insurable interest, the policyholder must stand to suffer a financial loss or detriment if the insured event occurs. For example, a homeowner has an insurable interest in their house because if the house were to be damaged or destroyed, it would lead to a financial loss for them. This requirement ensures that insurance is used for its intended purpose—to protect against genuine risks and losses—not for speculative purposes.

Other terms mentioned relate to different aspects of insurance but do not directly address the concept of economic loss due to adverse events. Co-insurance involves cost-sharing in a policy, abandonment refers to relinquishing rights to property, and premium adjustment relates to changes in insurance costs based on various factors. These terms do not convey the essence of having a direct financial stake in the outcome of an insured risk, which is why "Insurable Interest" is the correct choice.