Lifeless study displayed by court (6)
I believe the answer is:
wooden
'lifeless' is the definition.
(thesaurus)
'study displayed by court' is the wordplay.
'study' becomes 'den' (I've seen this before).
'displayed by' means one lot of letters go next to another.
'court' becomes 'woo' ('woo' can be a synonym of 'court').
'den' after 'woo' is 'WOODEN'.
(Other definitions for wooden that I've seen before include "Ligneous" , "Monotonous like timber" , "clumsy" , "Expressionless and dull, like timber" , "Stiff in manner, showing no expression" .)