Ih-diot
Similar to the common word idiot, an Ih-diot is a more advanced form of a moron. This term is pronounced more with the emphasis on the first syllable, as if there's an exclamation point after it. Compared to saying d'oh for someone else's stupid mistake.
Very insulting.
Me- "Did you know that Snook thought that an end table was actually a hen table?"

Scot- "No way!"

Me- "I swear he did!"

Scot- "Ih-diot!"