To protect or shield someone or something from someone or something that is dangerous, troublesome, or bad. We're building a fence to try to guard our vegetable garden from hungry animals. Cameron tries to guard his scrawny little brother from the school bully as much as he can. I'm sorry, I know it hurts you as a parent, but there's no way to guard your kids from bad and painful experiences.

to protect someone or something from someone or something. The assistant manager will guard your valuables from thieves. She guarded the kitten from the angry dog.