silly as a goose
(as) silly as a goose
Particularly foolish, silly, or frivolous. Everyone thought I was silly as a goose growing up—my head in the clouds, lost to dreams of impossible things. The government's proposed scheme to fix income inequality by overhauling the tax code in favor of corporations is about as silly as a goose.
*silly as a goose
very foolish. (*Also: as ~.) Edith is as silly as a goose. She thinks that reading aloud to her house-plants will help them grow. The ad in the newspaper said this lotion would make my hair grow back, but I've been using it for a whole month and my hair is still the same. Jane: You're as silly as a goose! Do you believe everything you read in newspaper ads?