(名詞) 負面或悲觀的思想、想法、觀念或解決方案。亦寫成 grey sky thinking, grey-skies thinking。
更負面或更悲觀的思想、想法、觀念或解決方案叫做 black-sky thinking, black sky thinking 或 black-skies thinking，這片語可追溯到約 2002 年。至於早已存在的 blue-sky 或 blue-skies，則可追溯到 1895 年，這是個形容詞，意為「過度樂觀的；不切實際的」；所以，blue-sky thinking, blue sky thinking 或 blue-skies thinking 意為「過度樂觀或不切實際的思想、想法、觀念或解決方案」。Grey-sky 和 blue-sky 為相反詞。
Policy-makers, when they lift their heads from the immediate and try to look ahead, described the process as "blue-skies thinking". But what is needed now is "grey-skies thinking", the politics of gloom.
—Charles Moore, "Financial crisis: We will find our catharsis in the politics of gloom," The Daily Telegraph, September 20, 2008
"Grey sky thinking" might be a better way of putting it. Officials at Glasgow City Council have been told to indulge in "blue sky thinking" in the quest for economies that could see its budget cut by 15% in three years and its workforce shrink by up to 3000.
—"Cutting to the quick," The Herald, September 24, 2009