Solution

The term "fungible" refers to something that is interchangeable with other items of the same type and value. "Interchangeable" accurately describes this characteristic because it means that one item can be replaced by another of equal value without any difference. Specific means clearly defined or identified, which is not related to the concept of interchangeability. Permanent implies lasting or enduring, which is unrelated to the concept of being replaceable. Outsmart means to outwit or be more clever than someone, which does not relate to the concept of fungibility.