The forbidden answer...
Use it if you want to
For example....
Jobo: hi fucktard!
Gaybi: shut the fuck up you idiot!
Jobo: fuck you!
Idiot
The best answer if someone is an idiot
For example...
Jobo: hey
Gaybi: idiot
Jobo: fuck you
Someone with a missing and/or partially formed frontal lobe
That guy is an idiot for seeing that brain surgeon