fungible

Fungible—which derives from the Latin verb fungi, meaning "to perform" (no relation to the noun fungus and its plural fungi)—is a word that often shows up in legal and political contexts. Something fungible can be exchanged for something else of the same kind. For example, when we say "oil is a fungible commodity," we mean that when a purchaser is expecting a delivery of oil, any oil of the stipulated quantity and quality will usually do. Another example of something fungible is cash. It doesn't matter what twenty dollar bill you get—it's still worth the same amount as any other twenty dollar bill. In contrast, something like a work of art isn't fungible; a purchaser would expect a specific, identifiable item to be delivered. In broader use, fungible can mean "interchangeable," or sometimes "readily changeable to adapt to new situations."