blue-sky ˈblue-sky adjective [only before a noun]
blue-sky thinking is thinking of ideas or solutions that are completely new and different from anything that people have thought of before:

• Some blue-sky thinking was needed to try and solve the pensions’ crisis.

• Toyota's blue-sky approach has completely changed the way its cars are made.

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blue-sky UK US adjective
blue-sky thinking — Cf. blue-sky thinking

Financial and business terms. 2012.