To infuse is to steep something in a liquid to extract the flavors from it. You'll impress your friends with your cooking if you infuse rosemary and thyme in broth and then use the liquid to marinate chicken.
To infuse also means to inspire or fill with a certain quality. Your goal might be to infuse your writing with such humor that your readers laugh until they cry. The medical meaning of infuse is to introduce a medicinal therapy through a patient's vein. When you're badly dehydrated, doctors may need to infuse you with fluids. The Latin root infusus means "to pour into."