scared stiff

literally not-comparable

(literally) scared to the point of being unable to move, or (figuratively) very scared.

Japanese Meaning

身動きが取れないほど怖がる / 非常に怖がる、極度の恐怖を感じる

I was scared stiff when I heard footsteps behind me in the dark alley.

暗い路地で後ろから足音が聞こえたとき、私は動けないほど怖くなった。

Sense（1）

(literally) scared to the point of being unable to move, or (figuratively) very scared.

He was scared stiff, like a deer in the headlights, by the vampire walking toward him.