I agree both Nitwit & Dimwit could be used. Only in instances such as this it is a great help to be able to be on the same wavelength as the compiler. In the MOS it is Chris Feetenby, and his main bible is "Collins English Dictionary". Now Collins gives Idiot as: 2 a FOOLISH or senseless person; Dimwit as: a stupid or silly person and Nitwit as: a FOOLISH or dull person. From this it can be seen that Idiot should therefore be NITWIT and not Dimwit as the only common factor is FOOLISH.