quake

To tremble violently with fear or nervousness. My brother is so strong and scary-looking that he leaves people quaking like a leaf when he threatens them. I was quaking like a leaf when I went up to deliver my speech.

To tremble with fear or nervousness. (Sometimes said sarcastically.) My brother is so strong and scary-looking that people quake in their boots when he threatens them. Ooh, I'm really scared of you! I'm quaking in my boots, you frighten me so!

to shake as with fear, terror, etc. Alice was quaking with fear as the door slowly opened. Todd quaked with terror when he saw the vicious dog at the door.

Fig. to be afraid; to shake from fear. I was shaking in my boots because I had to go see the manager for being late. Stop quaking in your boots, Bob. I'm not going to fire you.

to be very frightened or anxious My first teacher had one of those deep, booming voices that had you quaking in your boots.

Also, shake in one's boots; quake or shake like a leaf . Tremble with fear, as in The very thought of a hurricane blowing in makes me quake in my boots. Both quake and shake here mean "tremble." These idioms were preceded by the alliterative phrase shake in one's shoes in the late 1800s. The idioms with leaf allude to trembling leaves, as in He was shaking like a leaf when the exams were handed back. A similar expression was used by Chaucer, who put it as quake like an aspen leaf, a particularly apt comparison since aspen leaves have flattened stems that cause the leaves to quiver in the gentlest breeze.