You could say that the cowardly lion was " chicken-hearted."

你可能会说狮子胆小如鼠。

It was sometime before the cowardly lion awakened, for he had lain among the poppies a long while, breathing in their deadly fragrance.

这只胆小的狮子过了一段时间才醒来，因为他已经在罂粟花丛中躺了很长时间， 呼吸着罂粟花的致命香气。