Lacking individuality, unlike Hamlet for example (13)
I believe the answer is:
characterless
'lacking' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for characterless that I've seen before include "Lacking distinctive qualities" , "Dull" , "Lacking a distinctive nature" , "Nondescript" .)