The most common and most likely answer to this crossword clue is the 6 letter word SMARTY
I've seen this crossword clue in The Daily Telegraph
S
M
A
R
T
Y
More clues leading to the result SMARTY
Buddy explains!

The straight part
We know that "Would-be clever figure" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case would-be clever figure = smarty.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does SMARTY mean?
SMARTY noun- An obnoxiously clever or quick-witted person.