to shake a lot because you are nervous or frightened.
I saw her just before her talk and she was shaking like a leaf.
(usually in continuous tenses)
shake like a leaf
To tremble violently with fear or nervousness. My brother is so strong and scary looking that he leaves people shaking like a leaf when he threatens them.I was shaking like a leaf when I went up to deliver my speech in front of all those people.
shake (or tremble) like a leaf
tremble greatly, especially from fear.
shake like a ˈjelly/ˈleaf
(informal) shake with fear; be very afraid or nervous: Before I went into the exam room I was shaking like a leaf.