A person who isn't real bright, but is capable, and sometimes very good, at enough things in life to succeed.
Tim is a functional idiot. He may be a little slow, but he's a great mechanic, and is well liked around the shop.
by someguy1985 November 07, 2015
A person who suffers from functional idiocy.
The clear winner of the competition for Chairman of the Fraternity's Event Planning Committee was the best looking, most popular, functional idiot on the board.
by ljgunner September 08, 2009