Goon

A person who is so stupid they cannot do anything, not even to save their life

some symptoms of being a goon are as followed:
-lack of intellect
-lack of awareness
-having a punchable face

Note: not to be confused with goon which is a low ranking member of a group of syndicate, the context of this term is to be used an an insult for dumb people.

Man my brother is such a Goon