Foon

Meaning a diminutive fool. I first heard this being defined in a Panel show. The show in question was 'Call my Bluff' hosted by Robert Robinson. The program was broadcast in the early seventies, (with this line up). The team captains were Frank Muir and Patrick Campbell. The three people in each team would define an obscure word and the opposing team had to work out the true definition. One word that has, for whatever reason, stayed with me was Foon - a diminutive fool.
A few fragments still exist on you tube.

Foon would, obviously, be used in a derogatory way, as a descriptor. He/She is a real Foon.