1. cause in someone or personally experience a temporary feeling of fear or nervousness
get the jitters before giving a speech
The verb 'jitter' refers to a movement which is irregular, unsteady or shaky, particularly with an electrical signal. If someone 'has the jitters', therefore, it means they are shaky or unsteady due to nervousness. When you have the jitters you can be fidgety, nervous, or find it hard to remain calm. This is an informal phrase.