A kidiot is a combination kid and idiot; basically a kid that has so little a clue as to what he/she is going, that they just BS their way through it.
Some Kid: Did you hear that new Pokemon game just came out?!
You: Dude... STFU... Pokemon is gay.
Some Kid: NUH UH! im gay im gay blah blah blah I WIN!!! POKEMON ROX!!!
You: Bah. Riddled by another kidiot... I feel dumber just by being in your presence!
a kid that is an idiot; stupid.
powder is a kidiot; enemy territory kids
A child who is especially incompetent. Word usually uttered by irate parents.
Child: Can I take the computer in the tub, Mommy?
Mother: Suit yourself, kidiot.
Referring to a child doing something dumb. Because sometimes children are just little stupid people.
That kidiot just tried to flush a teddy bear in the downstairs bathroom!
A person too stupid to understand cultural references, due to their young age.
Girl: Alright! I love s'mores!
Guy: S'more what?
Guy: You're killin' me Smalls... It's a quote from The Sandlot.
Girl: Who is Smalls? What's The Sandlot?
Guy: What a kidiot...