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)

• rub shoulders with
• rub shoulders with someone
• rub someone out
• rub someone's nose in it
• rub someone the wrong way
• rub someone up the wrong way
• rub the wrong way
• rub up the wrong way
• rude awakening
• ruffle feathers
• ruffle someone's feathers
• rule of thumb
• rule out
• rule out something
• rule someone with a rod of iron
• rule the roost
• rule with a rod of iron
• rum do
• rumpy-pumpy
• run across
• run across someone
• run across something
• run a fever
• run afoul of
• run afoul of someone