A wicked problem is a situation whose formulation is contested and changes as people attempt to address it. Stakeholders disagree about values and boundaries; interventions have delayed or distributed consequences; and no final test proves that the problem is permanently solved.
The term does not mean that evidence is irrelevant or that action is impossible. It means problem framing, stakeholder power, learning, and adaptation are part of the work.
Example
Housing affordability involves land, finance, wages, transport, planning, construction capacity, neighborhood interests, and public policy. An intervention in one part changes incentives elsewhere.