### Clue: Expert on board that is diminutive figure (7)
### Answer: SHORTIE 
 ### Explanation: Definition: diminutive figure
 Edit.note:  Thanks Raich for the shorter explanation.  I thought wrongly. ~~Double defn: 1st: (I think) Short for a short seller, one who sells shares that he/she does not have yet in anticipation of a drop in price, in the stock exchange, the metonym of which is "the board" – presumably he/she's got to be expert in it to keep on doing it; and 2nd: a~~
SHORT(Nigel, English chess prodigy, grandmaster at 19, expert on chess board, and of whom I was shamefully ignorant) + IE(that is;Latin id est).
Answer:  A belittling word for a person of little;diminutive;short figure.