David, the figure from the cast, for instance, is broken leaving Buster Keaton (6)
I believe the answer is:
statue
'buster keaton' is the definition.
The definition suggests a singular noun which matches the answer.
'david the figure from the cast for instance is broken' is the wordplay.
I cannot really see how this works, but
'figure' could be 'stat' (I've seen this before) and 'stat' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'leaving' acts as a link.
Can you help me to learn more?
(Other definitions for statue that I've seen before include "Artistic work" , "With which Bartholdi achieved eminence" , "Stone figure" , "Solid representation of the human form" , "Three-dimensional representation" .)