stuff

Stuff is what makes up something; the things that it is made from.

Example: What is all that stuff on your bedroom floor?

When you stuff something, you put a lot of things inside of it; you compress things into it.

Example: She stuffed the turkey for Thanksgiving using her secret stuffing recipe of diced bread, onions, and celery.

To be happy and satisfied, usually to do with food.

Example: I'm stuffed after having eaten all that turkey, mashed potatoes and delicious stuffing.