Is a verb as an adjective? Actual is an adjective. The word actual is a verb. A Dark, black cat walked across my porch. Which animal did it follow? In your sentence, one of the adjective is preceded by not, so it is more like (bad example, but just bear with me): The dark, not white cat walked across my porch. One comma is enough for this to be passed.

Both adjectives apply to the noun, so in your case the harm, is both potential and not actual.