草木皆兵cǎo mù jiē bīng

《晋书·苻坚载记》：淝水之战，苻坚看到东晋军队阵容严整，又远望八公山，把山上的草木都当成晋军，十分恐惧。后用以比喻惊慌失措、猜忌敏感的心态。

英every bush and tree looks like an enemy—a state of extreme nervousness,as if surrounded by enemies; apprehend danger in every sound;