A patient describes constant, free-floating unease that is present most days regardless of circumstances, with no particular object or situation she can identify as triggering it, and no specific avoidance behaviour, since there is nothing obvious to avoid. Before revealing the answer: is this a phobia?

No, this is more consistent with generalised anxiety than with a phobia. A phobia requires a specific, consistent, identifiable trigger that drives avoidance behaviour; here, the unease is free-floating, not tied to any particular object or situation, and there is nothing specific for her to avoid. This lack of a clear, reliable trigger, together with the constant rather than situationally provoked quality of the fear, is what points toward generalised anxiety rather than a phobia.