But legally speaking yes.... practically though it's unenforceable unless you have witnesses and/or clear documentation for said item and it has a minimum value... to be worth it..
Stealing means to take something without permission from the owner without any intent to return it. So hypothetically, if you asked them, and then for some reason or another, you weren't able or forgot to return it, that wouldn't be stealing. That would just be taking something without ever returning it. Or being forgetful.