A complete numpty who is too stupid and inept to realise just how stupid and inept he really is. Also thinks he's a bit clever - usually a bit of a slap-head as well...

AKA Fake news CNN Brian Stelter

a legitimate idiot. this person is a complete fatty that is a straight up unco at everything and can not do anything right.
a straight up sped who is pretty useless.

One who is doesn't care to think things through or plan ahead.
A vacuous individual, a mental couch potato.

A potatohead (abreviation: KK, from german "Kartoffelkopf") is a human with a potato-shaped head. However, the potato shape of the head is not disadvantageous to his / her prettiness, but rather an unique feature of the respective human's beauty.

A potatohead is usually owned by a potatoheadowner (abreviation KKB from german "kartoffelkopfbesitzer"), who normally is a male person, as women usually rather match the criteria of a KK.

Someone with a head that looks uncannily like a potato.

Anyone who embodies the stereotypical variations (i.e. big head, slanty eyes, below average member size) characteristic of the asiatic races.