Stunad is an adjective usually one usually uses to describe themself. Usually used to describe the way you feel when you first wake up and can't yet mentally process anything meaningful or when you do something really stupid or a series of really stupid things, not because your stupid but because you're mentally not with it. This word is a little less harsh than stupid and has the connotation of being a bit silly.
I'm so stunad today. I put the milk in the cabinet and the salt in the refrigerator.
Talk to me after I drink my coffee then I won't feel so stunad.